A simple database might be a single file containing many records, each of which contains the same set of fields where each field is a certain fixed width. Research databases typically index hundreds of journals in a discipline. They may also include book chapters, dissertations, reports, and other materials. You can search for words in specific fields, or anywhere in the record. Note the various fields, such as Author, Title, Appears In, and Abstract.
Most research databases use only certain words to describe the articles that are indexed.
By using a defined set of subject headings, articles about similar topics are brought together, giving precise, comprehensive search results. You will often need to consult the thesaurus for the database you are using to determine the best subject headings. The entry shows narrower and related terms. Each database will have its own thesaurus, which means you may need to change the term you are using depending on the database you are in. Free-text searching can be very powerful, but also misleading.