The thesaurus allows you to find subject terms to narrow or broaden your search. Subjects are also commonly known as descriptors, controlled vocabulary, and sometimes classification terms.
To use the thesaurus, select the Thesaurus link from the Advanced Search, then browse or search for subjects containing the word or beginning with the word. Mark the items that you would like to search and then select the appropriate Boolean operator to combine your items. Click the Add to search button and your terms will be placed into the search form.