In developing search strategies, many times keywords will be all you need. However, if you don't guess the term the author used for your topic, you will not find that article. In indexed databases, such as PsycINFO, MEDLINE, CINAHL or ABI INFORM Global, no matter what term(s) an author uses (or neglects to use), there will be one subject term applied for that topic. Using subject terms can be really powerful addition to your overall search strategy!
Read further below for more details:
Keyword searches
will look for your search terms anywhere in the record -- e.g., in the title, abstract, subject heading, or other notes. Keyword searches may be less precise or relevant than searches using subject terms and may return a larger, but less useful, set of results.
Subject searches
on the other hand, only return results in which the search term appears in the subject field. The subject field contains “Subject Headings” or “Descriptors” - labels pulled from a special list (“thesaurus”) that are used as a way to connect related items and retrieve them all with one search. The tricky part of subject searching is finding the official subject heading/descriptor words that when searched will pull together all of the related items.
Most databases offer a thesaurus that helps you identify subject headings. You'll find the thesaurus in the Advanced Search of most databases.
Watch this informative video to see how subject terms can be used in a search