Some databases call the subject terms a thesaurus. Either way, find a list of the taxonomy of terms used in the database.
Select OR, AND, or NOT from the drop down menu, then click "ADD." The terms will be added to your search box. Click "Search."
Check the column on the left for "facets" or ways to further limit your search results.
Combine Searches with AND (limits search) or OR (expands search).