A controlled vocabulary thesaurus organizes a database into pre-determined subject terms that everything about that subject falls under. You do not have to guess among a host of terms that are similar in meaning to find relevant articles. SO it tells you what term is used that everything falls under.
You can also use a thesaurus to find other terms that mean the same or similar thing, or are similar in meaning to the term that you first used in case you do not find relevant results.
Example: employee Motivation --------- employee morale
Contains business-related journal and magazine articles, company profiles, market research reports, case studies, conference papers, country economic reports, and SWOT analyses.