The controlled terminology of subject searching has precise results that finds relevant articles. A thesaurus provides consistent headings so that all the sources on a specific topic use the same terminology. This way, if users know what term to use, they can retrieve all the sources on a specific topic even through there may be a number of ways of stating the idea.
Most databases have subject headings or descriptors for each item indexed.
These headings are found in the subject or descriptor field. Controlled vocabulary searches usually produce the results that are most likely to meet your needs, but you need enough time to determine what the correct terminology is. If you don't have a thesaurus handy, a good strategy is to do a keyword search to locate useful citations. Then, check the subject headings or descriptors within the records to identify the correct terms. A keyword search retrieves words or phrases from the various fields of the record.