PubMed indexes articles using a controlled vocabulary, Medical Subject Headings (MeSH®). A specific set of terms is assigned to describe each article. This provides consistency and uniformity so all articles about a certain subject will be retrieved, even if different terms for the concept are used in the article, like myocardial infarction and heart attack.
MeSH terms are arranged in a hierarchical categorized manner called "MeSH Tree Structures" and are updated annually.
Familiarity with this vocabulary will make you a better PubMed searcher.
Demonstrates features of the MeSH database that can be used to create a more targeted subject search.