This doc describes how to use Boolean search to retrieve records from EuropePMC via Application Program Interface (API).

EuropePMC combines results from the following databases:

• PubMed and PMC,
• The Agricola agricultural library,
• Preprints from 24 different life-sciences-related preprint databases.

Boolean Operators can be used to specify the structure of your search.

When entering your search terms of interest, use:

• AND/OR/NOT to separate terms,
• quotation marks to search for an exact term (which also turns off Automatic Term Mapping), and
• parenthesis to dictate groupings and priority order

to narrow in on publications of interest. For example,

stroke AND (trevo OR solitaire) AND “modified Rankin Scale”

will retrieve all EuropePMC-indexed publications that contain all of the following in their title, abstract, or keywords:

• The word stroke or similar terms to stroke (using Automatic Term Mapping [ATM])
• The word trevo or the word solitaire and associated ATM
• The exact phrase “modified Rankin Scale.”

If you want to specify how a term will be interpreted by PubMed, specify the field in the following manner: term[FIELD], using one of PubMed's pre-specified fields (or filters), which will narrow how that specific term is interpreted.

Fields and filters generally follow the structure of term[FIELD], but if the field is incorrectly spelled or not recognized, it will be ignored by PubMed and the term will be searched as plain text.

PubMed indexes articles using theMeSH controlled vocabulary, which means that you can add this field to search for MeSH topics so long as your term of interest is in the MeSH hierarchy.

• [MESH] / [MEST TERMS]: Searches throughout the MeSH hierarchy.
• [MESH MAJOR TOPIC]: Searches only for MeSH “Major Topics” (which are indicated in the MeSH hierarchy by asterisks).
• [MESH SUBHEADING]: Searches for only non-Major Topics in the MeSH hierarchy.

So, a search for stroke[MESH MAJOR TOPIC] will return only studies tagged with Major Topics at or under “stroke” in the MeSH hierarchy, while a search for stroke[MESH] will return any study tagged at or below “stroke” in the hierarchy.

Note: MeSH field searches will still be mapped by ATM, but only across the relevant MeSH fields.

PubMed enables searches to be narrowed by the following study characteristics:

• Publication type, by searching for one of PubMed's supported publication types using, for example, review[PT];
• Full Text available, by appending full text[SB];
• Publication date, by searching for YYYY-MM-DD[Date - Publication] : YYYY-MM-DD[Date - Publication])) (only the Year is required for the filter to function);
• Language, by searching for the language[LANGUAGE];
• And others (see full list here)

You can also narrow the section of the publication in question that your term will be searched within by specifying:

• Title only, term[TITLE]
• Title or Abstract (TIAB), term[TITLE/ABSTRACT]
• Text only, term[TEXT WORD]

See also our guidance on the following search creation tips, which match across PubMed and EuropePMC:

• PICO
• Expanding or Narrowing?
• How many records is "enough," and When to stop?