Medline® Advanced Search Field Tags

Use these two-character field tags to return more relevant results when building advanced search queries.

Field Tag



Searches for institution and/or place names in the Addresses field.

AI=Author Identifiers

Searches for Web of Science ResearcherID numbers and ORCID identifiers in the Author Identifiers table within a record. Enter a unique Web of Science ResearcherID number or ORCID identifier with the AI field tag.


Searches for author names in the Author(s) field within a record. Last names containing a space should be searched with and without the space to ensure that all relevant records are returned. For example: AU=(De Marco* OR DeMarco*) AU=(Van Hecke T* OR Vanhecke T*) See also Guidelines for Searching Names


Searches the Chemical table within a record.

CPD=Collaborating Partner

Searches the following fields within a record. Investigator(s) Keyword List Note Space Flight Mission

GI=Grant Information

Searches the ID and Agency fields in the Grant Information table within a record. The table contains the research grant or contract number (or both) that designates financial support by any agency of the United States Public Health Service or any institute of the National Institutes of health. The data are recorded exactly as they appear in the published article. The Agency fields contains the institute acronym. Data was captured starting in 1981.

GP=Corporate Author

Searches for institution names in the Corporate Author(s) field within a record.

IC=Identifying Codes

Searches for codes in the following fields within a record. NLM Unique ID PubMed ID ISSN Date Created and Date Completed Molecular Sequence Data


Searches the ISSN field within a record.

The ISSN (International Standard Serial Number) searches for periodical publications such as journals and electronic publications. If a journal has both a print ISSN and an electronic ISSN, then both display in the Full Record. The format is four numbers, a hyphen (-), three numbers, and then a check character that may be a number or X.

MH=MeSH Heading

Searches the MeSH Terms table within a record.

MT=MeSH Major Topic

Searches the MeSH Terms table for subject headings designated as major topics within a record.

NL=NLM Unique ID

Searches the NLM Unique ID field within a record.

PD=Publication Date

Searches the publication date in the Source field within a record.


Searches the PubMed ID field within a record.

PY=Year Published

Searches the Source Published field within a record. You must combine this field tag with another field tag using the AND or NOT Boolean operator. Example: TS=cell growth AND PY=2007 When entering a range of years, restrict your search to five years or less; otherwise, processing slows down and the product returns too many unproductive results. Example: TS=cell growth AND PY=(2008-2010)

RN=Registry Number

Searches for a CAS Registry Number® in the Registry Number field within the Chemical table.

RO=Record Owner

Searches the Record Owner field within a record.

SO=Publication Name

Searches for publication names in the Source field within a record. The product retrieves all source titles within a product database (for example, journal titles and/or book titles if the product includes books).

SU=Research Area

Searches the Research Areas field.


Searches the Title and Vernacular Title fields within a record.


Searches for topic terms in the following fields within a record: Title Vernacular Title Abstract Other Abstract MeSH Terms Keyword List Chemical Gene Symbol Personal Name Subject Space Flight Mission