Library databases, which can include indexing/abstracting databases or repositories of full-text, are built with subject headings that link documents together. Subject headings are standardized terms that describe the subject matter or topical content of information sources.  Also known as preferred vocabularies, controlled vocabularies, or descriptors, subject headings are useful in the following ways:

• searches may lead to more relevant sources than keyword searches, in that they are only assigned to sources for which the heading is a main or important theme in the information source.
• all sources categorized under the same heading are collocated.  If you find a useful heading, you can find many relevant sources under that heading.
• subject headings can be used to find related headings as well as broader or narrower headings, and may be assigned as preferred terms, like with the thesaurus example below: "Conflict resolution" is used as a subject heading in place of "Dispute settlement."
   

How to find and search by subject headings
To identify subject headings in a database, look for a thesaurus or a subject browse feature.  In addition, subject headings may be found through preliminary keyword searches, displayed in individual records for the search results. 

Example: Subject Headings in NUsearch

You can "browse" by subject heading to see how items are linked together.


Example: Thesaurus Searching in Worldwide Political Science Abstracts

The database thesaurus offers similar words and phrases that it uses to link together items.

Another option is to use keyword searches to find subject headings. Example: a keyword search in Worldwide Political Science Abstracts on dispute settlements AND NGOs finds articles that are described with potentially useful subject headings.

The most effective strategy is to try searching with multiple sets of subject headings and keywords to explore the various ways your subject has been described over time.