When you run a simple search composed of just a few keywords, PubMed uses a process called automatic term mapping (ATM) to translate those keywords into MeSH terms.
Think of MeSH (Medical Subject Headings) as the index to the book that is PubMed. It is the National Library of Medicine's controlled vocabulary (thesaurus).
When new material is added to the database, it is indexed by librarians at the NLM. The librarians read each article and add appropriate information (metadata) about the article that allows searchers to find the article more easily. In addition to standard metadata (such as publication type, sex, species, and age group), the indexer also adds 10 to 15 MeSH terms that describe what the article is about. These tags are selected from a standardized set of 30,000+ MeSH terms.
By using the exact MeSH wording as part of your search, PubMed can include not just that specific term but also its synonyms, subheadings, and spelling variations. Search sensitivity is often greatly increased as a result.
The really great thing about PubMed is that it will usually be able to automatically translate the keywords you enter into their corresponding MeSH terms and include both the keyword and the MeSH term in the search string!
NOTE The most recently added references may not yet be indexed with MeSH terms.
A To see which MeSH terms have been assigned to an indexed article, click the MeSH terms heading in the Page Navigation section along the right side of the abstract. The navigation options will vary depending on the article.
B MeSH terms assigned to a particular article will be listed in the MeSH Terms section. The terms marked with an asterisk (*) are flagged as major topics of the article, and MeSH subheadings follow forward slashes. In the example below, we can see that prevention and control of procedural pain is a major topic of this article.
C Each MeSH term in the list is a hyperlink that will allow you to incorporate the term in a new or existing search. Clicking on a term’s link will allow you to choose one of the following options:
D The easiest way to access the MeSH Database is to return to the PubMed homepage and click on MeSH Database in the Explore column.
E Type any term into the search box and PubMed will attempt to translate it into a MeSH term.
F If the database can’t find a perfect match, you will be presented with multiple options. For instance, searching the MeSH Database for knee (a very general concept) will pull up the results shown in the image below. Note that each option provides a scope note (a definition that describes how the term is used for indexing). These notes can be used to verify the term is the one that fits your search needs most closely. The capitalized words indicate related MeSH terms. The year introduced denotes the first year the term appeared in the index. (The term is searchable back to the earliest date shown.)
G If you know you want to search for articles that discuss knee replacement, you could either scroll down the list and click the appropriate term (using the scope notes as needed) or you could simply return to the search bar and type knee replacement. The full entry for the term Arthroplasty, Replacement, Knee is shown below. An explanation of the entry’s features can be found in the next section.
