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Subject Terms and Database Thesauri

Subject terms, also called controlled vocabulary, are specific words that have been assigned by a database to describe each book or article within. Library databases use searchable thesauri to arrange these subject terms. It is possible to search for articles using subject terms from database thesauri, rather than using keywords. You can also use thesauri for ideas on keywords to use in your database searches when you aren’t quite sure which keywords to try. Type in the term that best describes your topic and see what the thesaurus has that might better describe that topic and search with that word instead. Using the thesaurus can help you figure out which synonym to use, which spelling to use, or which combination of terms to use.

Since subject terms reflect the main focus of the book or article, searching by subject may be a quick way to narrow your results to a particular topic. However, subject searching should be used as a second step. Try a keyword search first, then see what subjects are recommended to you, or look at the subject headings for useful search results. Try adding those to the keyword search, or searching the subjects alone.
A lot of databases will show you “Suggested Topics” or “Suggested Subjects” once you have run your search. Look for these suggestions to find subject words that are related to your keyword search. Below is an example from ProQuest:

Using a database thesaurus or subject words is great as a starting point if you are struggling with finding keywords and need to learn about the terms that the database uses.

Not all databases have searchable thesauri, but many do. For a list of NCU Library databases that have searchable thesauri, see this Library FAQ: Database Thesauri. For other databases or websites, Look for a link that says “thesaurus,” “topics,” “subjects,” “descriptors” or “related terms.” Or look for the Advanced Search functionality. Some databases, like ProQuest, will also display subject terms from the thesaurus on your search results page. Using the thesaurus or suggested subject terms will help you broaden or narrow your topic and pick the appropriate terminology to find useful search results.

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