Using Limit Fields

Limit fields, when combined with other search terms, these are particularly useful for focusing or limiting a search. To search a limit field, use the in or = operators with the field abbreviation, such as index in pd or pd=index. Omitting the field label retrieves information from free text (non-limit) fields only.

Abstract Indicator (AI)

Accession Number (AN)

Document Type (DT)

ISBN (IB)

ISSN (IS)

Language (LA)

Language of Summary (LS)

Publication Year (PY)

Update Code (UD)

URLs Etc (XURL)

For limit fields containing numeric data, you can also use other special operators:

< less than,

such as py<1995

> greater than,

such as py>1992

<= less than or equal to,

such as py<=1996

>= greater than or equal to,

such as py>=1992

- indicates a range,

such as py=1992-1997