Database-specific search engine
Free
Broad spectrum healthcare
Broad spectrum related/other fields
Related areas e.g. biochemistry, toxicology.
Journal articles
eBooks
Primarily articles from scientific journals.
Broad spectrum of research designs
International
English
English
Daily
- In addition to MEDLINE, PubMedCentral (PMC) and Bookshelf can also be searched using the PubMed interface.
- All indexed references are given their own identification number (PubMed ID or PMID).
Basic functions
Search functions
If a search term is entered without any additions, MEDLINE automatically performs a similarity search (automated term mapping) via PubMed. The respective term is compared with various catalogs (MeSH terms, journals, authors, collaborators). If matches are found, the terms from the corresponding catalogs are included in the search. How the database deals with a search query is shown in the "Search details". These can be viewed in the "History and Search Details" under "Advanced Search". Click on "Details" for the corresponding entry under "History and Search Details". The following options deactivate the similarity search:
- Phrase search using quotation marks
- Use of search commands
- Use of hyphens (e.g.
cancer-related) - Use of wildcards
MEDLINE via PubMed has a so-called phrase index, which lists all words or word groups that can be used for phrase searches. The phrase index can be called up in the advanced search under "Show index" and by entering it in the search interface you can check whether a phrase is present in the index and how many publications there are that contain the phrase.
If words or groups of words are placed in quotation marks that do not appear in the phrase index (e.g. "framing spaces"), the quotation marks are ignored and MEDLINE via PubMed carries out a similarity search. If the similarity search is deactivated by another input, e.g. a search command, 0 hits are displayed for the search term in question.
This must be taken into account when using the phrase search, as it can lead to relevant hits being overlooked. It is advisable to check the phrase index beforehand to see if there are any less common words or groups of words that are used for the exact word or phrase search. If this is not the case, it is advisable to omit the quotation marks for word groups so that AND is automatically added between the single words. Although this may result in irrelevant hits being displayed if the two terms do not appear in this exact order one after the other, it appears to be the only way to avoid a search term that does not return any hits.
As part of the basic search (input without search command and without quotation marks), the "Automatic Term Mapping" function enables PubMed to search for an entered search term in all search fields, including the keyword field.
The "Single Citation Matcher" search mode can be used to search very specifically for single hits indexed in MEDLINE via PubMed. It can be found on the main page of PubMed under "Find". In the "Single Citation Matcher" search mode, various fine adjustments can be made with regard to journal, date, authors and title words.
AND, OR and NOT. If there are spaces between two search terms, AND is automatically set.
*(replaces 0-n characters). The truncation can be set within a word or at the end of a word and is possible from four characters in the word stem.
"term1 term2"[field:~N], where term1 and term2 stand for the search terms to be searched for at a desired distance, field stands for the search field in which the terms are to be searched for and N stands for the maximum number of words starting at zero that can be placed between the two terms regardless of their order. Any number of terms can be placed in the quotation marks, the more, the more limited the search. Wildcards such as the * truncation cannot be used in combination.
E.g. would find "home care"[tiab:~2] matches containing home care, home centered care, home centered primary care, care at home or care at nursing home.
The *truncation also works within quotation marks, within or at the end of one or more terms.
Default setting in the simple search and in the advanced search (unless another search field is selected manually in the latter).
Only possible together with search in title, also includes the keywords associated with the abstract.
E.g. Author, Journal, Language.
Limited usability.
Limited usability.
Filter functions
Independently of the filter functions, PubMed has so-called Clinical Queries, which can be found on the main page under "Clinical Queries". These are search filters specially developed and adjustable by PubMed for the following clinical topics or publication types:
- Clinical Studies in various settings (e.g. Ethiology, Diagnosis etc.) with the option of a sensitive (Broad) or specific (Narrow) literature search
- COVID-19 in various settings (e.g. General, Diagnosis, Treatment The Clinical Queries are scientifically validated, but the validations of the filters for "Clinical Studies" date back more than 10 years. If you click on "See ... filter details", the respective filters are displayed there including information on sensitivity/specificity and can be copied from there into the search string.
The publication date can be narrowed down to the exact year using the slider in the timeline ("Results by year") on the left-hand side, to the last year, the last five or ten years or to a specific period to the exact day under "Publication Year" further down. The search can also be narrowed down to the exact day using search commands. The search can also be narrowed down to the exact day using search commands.
Together with document type under the filter "Article Type" .
Together with research design under the filter "Article Type" .
However, search command LASTAU possible directly in the search string.
E.g. Species, gender, age, selectable under "Additional filters" to the left of the hit list.
All selected filters are marked with a tick.
Display of search results
By publication date ("Publication date") or indexing date ("Most recent") in ascending or descending order.
"Best Match".
By first author in alphabetical ascending or descending order.
In alphabetical ascending or descending order.
Display of 10, 20, 50, 100 and 200 hits per page possible. By repeatedly clicking on "Show more results" below the hit list, the number of hits per page can be increased.
Search process and export
Individual components of the literature search can be deleted and/or combined with each other via the search history. When building complex literature searches, you can save time by clicking on "Add to history" instead of "Search" in the advanced search (click on the arrow next to "Search" and select this option, it will then be set as the default option for the button until you switch back to "Search"), as the respective component is added directly to the search history without displaying the hits.
Via e-mail and/or RSS feed.
Maximum of 10000 hits at once.
Support functions
Any error messages (e.g. open brackets or operators without an associated search term are ignored; this is displayed after the search process has been completed) or search terms not found are displayed above the first hit of the search results after the search has been completed.
Special functions
Important search commands
An overview of all search commands can be found here: Link.
Search term is searched in all fields.
Search term is only searched for in the title.
The search term is searched for in the title, abstract and keywords.
Limitation by publication date or publication period, which is written into the search string as a separate search concept.
The month and day can also be restricted using /. The following notation must be observed: yyyy/mm/dd[DP]
In addition, a time period can be defined using :.
This can be used to search for the first author of a publication.
This can be used to search for the last author of a publication.
This can be used to search for publications involving people from a particular institution.
Here you can search for publications for which an erratum has been published.
This can be used to search for publications in specific countries.
Controlled vocabulary
The index terms used by MEDLINE are referred to as MeSH Terms. These are listed on an independent page, the MeSH Browser, in a hierarchical tree structure. In this browser, search terms can be entered directly into a search field and checked for the presence of adequate MeSH terms (also known as descriptors). It is recommended to search for suitable MeSH terms for each search term individually and independently of each other.
In addition to superordinate MeSH terms and subordinate MeSH terms, subheadings (also known as qualifiers) are also assigned to each individual MeSH term (regardless of whether they are superordinate or subordinate). These are subcategories of the respective MeSH term. They are used to further specify or narrow down the search. Some of the subheadings are also organized hierarchically.
The subheadings are entered as follows: Mesh term/name of the subheading or MeSH term/abbreviation for subheading.
An overview of all subheadings that can be used in MEDLINE and their abbreviations can be found here: Link.
A list with the hierarchical arrangement of the subheadings can be found here: Link.
Not all subheadings are assigned to every MeSH term.
Example:
MeSH Term: Diabetes Mellitus
Superordinate MeSH term: Endocrine System Diseases
Possible subordinate MeSH terms: Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2
Possible diabetes-related subheadings: diagnosis (DI), rehabilitation (RH), therapy (TH)
Diabetes with subheading diagnosis: Diabetes Mellitus/diagnosis or Diabetes Mellitus/DI
PubMed also has an integrated search for MeSH terms on the site itself. It can be used by clicking on "MeSH Database" under "Explore" on the right-hand side of the main page of PubMed. The procedure described is only intended to find suitable MeSH terms with the MeSH browser in order to use them together with the other search terms in a search string in the normal PubMed interface.
Switch to the MeSH browser page: Link.
You should first set which hits are to be searched for. The following options can be selected for this:
- "Main Heading (Descriptor) Terms": Search for MeSH terms
- "Qualifier Terms": Search for subheadings
- "Supplementary Concept Record Terms": Search for (chemical) substances that are not listed in the MeSH terms
- "All Terms": Search for all entries named above The other options are very specific and can generally be neglected. For most literature searches, the setting "Main Heading (Descriptor) Terms" is recommended if you want to search for specific MeSH terms, especially as the associated subheadings of a MeSH term found can also be displayed later if desired.
You can then choose between two basic search settings directly to the right of the search field:
- "FullWord Search": searches for MeSH terms in which the search term entered represents the entire word (leads to fewer but more precise hits)
- "SubString Search": Searches for MeSH terms in which the search term entered only maps part of the word (leads to more, but less precise hits) As a MeSH term that matches as closely as possible should be found, the "FullWord Search" setting is a good choice. Only if no hits can be found with this setting and after exhausting the three options described in the next step should the "SubStringSearch" setting be selected. An exception is if it is already known that the search term entered is part of several words and these words (or the MeSH terms for these words) should also be found. In this case, the "SubStringSearch" setting is recommended right from the start.
The selected search setting can then be additionally specified by clicking on one of the following three buttons to the right of the setting in the previous step. This also starts the actual search process:
- "Exact Match": finds MeSH terms that exactly match the search term entered, regardless of whether they are superordinate or subordinate MeSH terms (leads to a single, but very precise hit)
- "All Fragments": finds MeSH Terms that contain the entered search term as part of the word (leads to more, but less precise hits)
- "Any Fragment": finds MeSH Terms that contain at least part of the entered search term as part of the word (leads to even more, but less precise hits) Since the aim is to find a MeSH Term that matches as closely as possible, it is a good idea to start by searching with "Exact Match". If no MeSH term is found, the search can be repeated with "All Fragments". If still no matches are displayed, "Any Fragment" enables an even broader search.
Depending on the search settings selected and the number of MeSH terms found, opens - a direct view of a specific, most suitable MeSH term or
- a list of potentially suitable MeSH terms found. Under "Sort by" these can be sorted either by relevance or name, and under "Results per page" the number of MeSH terms displayed per page can be set (only 20 or 1000 possible). The most suitable MeSH term can be selected from the list with a click and the direct view described above also opens.
In the direct view, general information on the respective MeSH term can be found under the "Details" tab, the subheadings assigned to the respective MeSH term under "Qualifiers" and the respective superordinate or subordinate MeSH terms in a tree view under "MeSH Tree Structures". The information under "Concepts" can generally be ignored.
MeSH terms found in this way can be entered into the PubMed search interface both on their own and in combination with associated subheadings for the actual literature search. The following search commands are available for this purpose, which can be entered in upper or lower case:
Search for all hits to which the MeSH term (or the MeSH term with a specifically entered subheading; without entering a subheading, all subheadings belonging to the MeSH term are taken into account) has been assigned; hits to which subordinate MeSH terms with their associated subheadings have been assigned are also automatically included.
Search for all hits to which the MeSH term (or the MeSH term with a specifically entered subheading; without entering a subheading, all subheadings belonging to the MeSH term are taken into account) has been assigned as the main term/main topic; hits to which subordinate MeSH terms with their associated subheadings have been assigned as main terms/main topics are also automatically included.
Search for all hits to which a MeSH term has been assigned with a subheading that cannot be entered together with the MeSH term (as it is not an "official" subheading associated with the MeSH term), must be linked to the respective MeSH term with the AND operator, also includes subordinate subheadings. It is also possible to search with the subheading alone without an associated MeSH term (e.g. ethics[TI] OR ethics [SH])
"No exploring", i.e. the automatic search for subordinate MeSH terms and/or subheadings for the top three commands is deactivated and only hits to which the specifically entered MeSH term and/or the specifically entered subheading is assigned are searched for.
Citation searching
Backward citation searching
Via "References" in the detailed hit view. Not available for all references and export functions not available.
Forward citation searching
Via "Cited by" in the detailed hit view. Not available for all references and export functions not available.
Export of results
Export of single hits
- Mark one or more matches found in the box to the left with a tick.
- Click on "Send to" at the top of the list of search hits and select "Citation manager". An interface opens in which you can select which hits are to be exported ("Selection"). Leave the default option ("Selection (n)") as it is.
- Then click on "Create File".
- All further steps depend on the browser and reference management software used.
Export of all hits at once
- Exporting all hits for literature searches with fewer than 10,000 hits: Click on "Send to" at the top of the list of search hits and select "Citation manager". An interface opens in which you can select which hits are to be exported ("Selection").
- Select the "All results" option there. Then click on "Create File".
- All further steps depend on the browser and reference management software used. The first 10,000 hits can be exported in this way.
- Export all hits (for literature searches with more than 10,000 hits): Carry out steps 1-3 described under "Exporting all hits". This will export the first 10,000 hits.
- Click on the cogwheel at the top right above the hit list. In the window that opens, select 200 as the maximum number under "Per page". This will display 200 hits per page.
- Click on "Jump to page" below the hit list, enter "51" in the window that opens and then click on "Jump". This will take you to the page with the first 200 hits that have not yet been exported, i.e. the page starting with hit 10001.
- Click on "Show more" at the bottom of the results bar to display the next 200 results on the same page. Continue to click on "Show more" until all remaining hits are displayed on one page.
- Then click on "Send to" at the top of the list of search hits and select "Citation manager". An interface opens in which you can select which hits are to be exported ("Selection"). Select the option "All results on this page". Then click on "Create File". In this way, more than 10,000 results can be displayed or exported at once on one page.
- All further steps depend on the browser and reference management software used.
Export of all hits (alternative)
Alternative solution for more than 10,000 hits: It is also possible to use the slider at the top left of the hit list to limit the publication period so that there are fewer than 10,000 hits and to export these individual segments of the publication period separately until all hits have been exported. The procedure is described below using the search string cancer AND fatigue as an example. The search was carried out on January 14, 2020 and returned 23272 hits at that time. However, this procedure is risky because the number of hits exported in this way may differ slightly from the total number of hits displayed (in our example, the difference is exactly 1 hit, but it may be more). This procedure should therefore be used at your own risk.
- Using the slider from the most recent date as the starting point, adjust the time period down so that there are fewer than 10,000 hits. In the case of our example search string cancer AND fatigue, this would be the period 2020-2014, which yields 9855 hits (as at: 14.01.2020). Then apply steps 1-3 described under "Export all hits" to export all hits from this period.
- Use the slider to define a further period with less than 10,000 hits from which no hits have yet been exported. Make sure that the respective time periods do not overlap. It makes sense to take the year under the oldest date of the period defined in the previous step as the starting point. In the case of our example search string cancer AND fatigue, this would be the period 2013-2003, which returns 9954 hits (as at: 14.01.2020). Then apply steps 1-3 described under "Export all hits" to export all hits from this period.
- This procedure should be continued until all hits have been exported. In the case of our example search string cancer AND fatigue, this would be the period 2002-1928, which brings the last 3762 hits (as at: 14.01.2020).
Related links
- Help section of PubMed (English): Link.
- Help page of the U.S. National Library of Medicine regarding MeSH terms with interesting facts, current developments and tutorials/webinars (English): Link.
- List of journals indexed in MEDLINE via PubMed: Link.
- Homepage of the InterTASC Information Specialists' Sub-Group (ISSG) with search filters: Link.
- The Pubservatory tool of the ZB Med shows current changes in PubMed: Link.
- Training site The PubMed Trainer's Toolkit: Link.