Several of EBSCOhost's secondary databases support a thesaurus (MEDLINE, CINAHL, Environmental Policy Index and ERIC). The thesaurus features an option called Major Concept that will focus the search. When an article is indexed in these databases, any heading associated with it will be classified as a major or minor heading depending on the subject content of the article. A subject heading is major when it describes the main focus of the article. A subject heading is minor when the subject content is discussed in the article to some degree, but the main focus and content of the article is on a different subject .
A thesaurus or MeSH search can be limited to articles which contain only a subject heading as a main focus of the article by checking the box Major Concept. Leaving this check box blank will search for the heading as both a major and minor concept in an article. If you choose to search the heading as a Major Concept, the term will be added to the Find field with "MM" (the tag associated with Major Concept) in front of it. Otherwise, the term will come after "MH". This "MH" search will search for articles which contain the term as either a Minor Concept or as Major Concept. This will retrieve more results then searching only for Major ("MM") Concepts.