While not necessarily “secret”, field codes are an underutilized feature found in nearly all scholarly literature databases.
A field is a specific part of a record found within a database. A field code (also sometimes referred to as a field tag) is a word, abbreviation, or letters that are tied to a specific field within a record. Some common examples of fields are: title, author, and publication year. Every database has their own set of field codes for the various fields found in their records. Here we discuss how you can leverage these field codes to focus your literature searches.
Adding Field Codes to your Search
The default, or basic search, in most databases, is a general all field or keyword search. While this may be fine for simple searches, as searches become more complex, sometimes there needs to be more options available. That is where field codes come in.
The Advanced Search features found in most databases is where you can manipulate your search strategies to include field codes. In some cases available or common field codes are listed on this page. Depending on the database, you may or may not be able to add multiple field codes to a single search. If you are limited to a single field code, use the Boolean Operator OR to combine multiple search strings.
Commonly Used Field Codes in Select Databases
PubMed
PubMed refers to their field codes as “field tags“. Since PubMed is tied to the MEDLINE database, it draws their fields (also known as elements) from MEDLINE records. Not all elements (fields) are mandatory or appear in every record and other elements may be found in multiple fields. Not all MEDLINE fields are searchable in PubMed.
For more detailing instructions on how to search field tags in PubMed, see the PubMed User Guide: Using Search Field Tags.
| Field | Tag | Notes | Example | |
| Article Title | [ti] | Can only be combined with Abstract [tiab] | “breast cancer”[ti] | |
| Abstract | [ab] | Can only be combined with Title [tiab] | “breast cancer”[ab] | |
| Publication Date | [pd] | Dates or date ranges must be searched using the format yyyy/mm/dd [dp] (month/day are optional) | 2023[pd] | |
| Date Range | [pdat] | To enter a date range search, insert a colon (:) between each date | 2020/01/01:2023/12/31[pdat] | |
| Journal Title | [jt] | Full journal title, taken from NLM’s cataloging data | “New England Journal of Medicine”[jt] | |
| Journal Abbreviation | [ta] | Standard abbreviation for the title of the journal | NEJM[ta] | |
| Author Name | [au] | Last name followed by a space and up to the first two initials | Thompson CB[au] | |
| Affiliation | [ad] | Prior to 2014 only first author affiliations were included | “Memorial Sloan Kettering Cancer Center”[ad] |
Embase
Embase allows for field codes to be used both with phrases and search strings, as well as with individual exact phrases. Not all field codes can be used interchangeably.
Phrase Searching
The majority of field codes in Embase allow for phrase searching, which is identified by :xx. In this context, phrases can be combined using Boolean operators and searched across multiple field codes.
A phrase (‘breast cancer’) can be searched in specific fields and it will identify that term or phrase anywhere in the fields searched. So a search for ‘breast cancer’:ti,ab,kw will search the title, abstract, and author keywords fields for the phrase ‘breast cancer’ found anywhere in any of those fields.
Exact Searching
An exact search, identified as /xx, can be used when trying to retrieve an exact match, such as identifying articles published in the journal Heart. In this case, a phrase search in the source title field (‘Heart’:jt) would retrieve all articles from all journals with the word heart included. If we just wanted the exact journal Heart we would instead search ‘Heart’/jt.
To read more about using field codes in Embase, refer to their Embase FAQs: What field codes can I use in Embase?
Note: MSK Library provides access to the Embase database on the Elsevier platform. Field codes and searching will differ if you are searching Embase on another platform.
| Field | Code | Notes | Example |
| Article Title | :ti | *Combined :ti,ab,kw,etc | ‘breast cancer’:ti |
| Abstract | :ab | *Combined :ti,ab,kw,etc | ‘breast cancer’:ab |
| Author Keyword | :kw | *Combined :ti,ab,kw,etc | ‘breast cancer’:kw |
| Publication Year | :py | Singular year | 2013:py |
| Publication Date | :pd | Singular date | 1964-01-01:pd |
| Date Range | /py | Span of years | [2013-2015]/py |
| Source Title | :jt | Title of source publication (journal, book, etc) | ‘new england journal of medicine’:jt |
| Abbreviated Journal Title | :ta | Abbreviated title of journal | ‘nejm’:ta |
| Author Name | :au | Last name space first two initials with periods | ‘thompson c.b.’:au |
| Author Affiliation | :ff | Author’s affiliate organization | ‘memorial sloan kettering cancer center’:ff |
| Author Address | :ad | Author’s address (city, state, country) | ‘new york’:ad |
Web of Science
The advanced search field tags in Web of Science allow for users to focus their searches on a variety of fields within the Web of Science Core Collection. There is no way to combine field tags, so in order to search a term or phrase in multiple fields, requires combining two or more strings with the boolean operator OR.
The easiest way to bypass this limitation is to use the topic field tag (TS) which searches the article title, abstract, as well as author keywords in a single string.
One big benefit of using field codes in Web of Science is the ability to search by author identification, includes either Web of Science’s ResearcherID as well as ORCID.
For detailed descriptions and available field tags in Web of Science, refer to Web of Science Core Collection Help: Advanced Search Field Tags.
| Field | Tag | Notes | Example |
| Topic | TS | Searches title (TI), abstract (AB) and author keywords (AK) fields in one string | TS=(“breast cancer”) |
| Title | TI | Searches article title in journal, book, or conference proceeding | TI=(“breast cancer”) |
| Abstract | AB | Searches abstract field | AB=(“breast cancer”) |
| Author Keywords | AK | Searches author keywords field | AK=(“breast cancer”) |
| Publication Year | PY | Searches both early (electronic access date and final publication year | PY=(2021) or PY=(2010-2022) |
| Publication Title (Source) | SO | Searches all source titles (journals, books, proceedings) | SO=(“new england journal of medicine”) |
| Author Name | AU | Last name space first initial | AU=(Thompson C) |
| Organization | OO | Organization or institution name | OO=(“Memorial Sloan Kettering Cancer Center”) |
| Address | AD | Organization or institution address | AD=(“1275 York Avenue”) |
| Author Identifiers | AI | Web of Science ResearcherID numbers and ORCID identifiers | AI=D-2427-2012 |