Keyword and subject terms searching can be combined. For example, rather than guessing what keywords to use consider doing a thesaurus (controlled vocabulary) search first. Review and assess your results. Then, add a keyword search to the query or use Search History to combine searches.

Identify all the major concepts of your thesis or research topic. Then use the thesaurus or subject index to locate, explore and select subjects (also known as descriptors) for each concept of your topic.

About Subject Headings
Whereas the common keyword search is based on an exact word match, a subject or thesaurus search locates records by assigned subject or descriptors.

Subject headings, descriptors and thesauri terms are examples of "controlled vocabularies." They are lists of pre-defined, carefully selected words and phrases used to classify and organize information. Controlled vocabulary describes the general content of an information unit, such as a book, an article, or an essay. searching with controlled vocabulary in a subject index or thesaurus allows you to more precisely retrieve relevant information on your topic, illustrates relationship between related terms and helps you identify synonyms and broader and narrower terms.

As shown in the chart below, controlled vocabulary varies with discipline and database and may be identified as subject heading terms or a thesaurus. Click a database title then look for, and use, the subject or thesaurus link (located in the top menu bar).

Use Subject Headings and Thesauri to:

• get ideas
• browse related, broader and narrower topics of interest
• get specific, targeted results
• combine with keyword searching for more focused results