Have you ever used the index at the end of a textbook so you could do a worksheet without reading the whole chapter? That index was created to enable you to find information with greater ease. The same has happened to the information in a database. There are people whose jobs are to review and analyze articles in the database. Every article from every source in the database, whether from a magazine, book, web site or other source, is analyzed and assigned subject headings so that you can find the article that answers your question.
Be aware what type of search you are using. Most databases open to a Subject search, which will only look at the subject headings that have been assigned to an article. These subject headings might use the terminology you are using, but they might not. Most databases have separate search screens for Subject, Keyword, Title, Author, and Journal or Source.