All About PubMed

Using MeSH to Search

Medical Subject Headings (MeSH) is a list (thesaurus) of keywords or descriptors that describe articles in MEDLINE. Indexers scan an entire article and assign up to twenty MeSH terms to each article. Terms are chosen to cover an article's central aspects (major headings) and other significant information discussed (minor headings).

By using terms from the MeSH thesaurus, all articles on a given topic can be found regardless of the terminology used by the authors.

Use MeSH to:

• Identify appropriate terms
• Confirm definitions
• Search by a subject
• Build a search strategy
• Apply subheadings
• Focus search results
• Limit or expand retrieval

MeSH Database:  Search

Links to MeSH are found on the PubMed Home page under Explore and at the bottom of the Advanced Search screen. The MeSH database allows you to search for and select specific MeSH (Medical Subject Headings) and subheadings to focus your search. Learn more about MeSH from the National Library of Medicine.

Note: Searching with only MeSH terms excludes the most current citations in-process and publisher-supplied citations as they are not indexed with MeSH.

• For a more detailed listing of subject heading terms, see NLM's MeSH Browser.
• For MeSH indexing hints, see below.

History/Advanced Search

Search by Field

There are two ways to limit your search term(s) to a specific field:

1. Search for words or phrases in a specific field using PubMed Search Field Tags. Place the two-letter abbreviation for the field in square brackets after the search terms. Examples:

   asthma[ti]  will limit asthma to the the title of the article

   asthma[majr]  will limit asthma appearing as a major Medical Subject Heading (MeSH).  Note: term chosen must be a established MeSH term

2. You can also designate fields for searching by using the Advanced Search Builder on the Advanced Search page. Use the pull-down menus to select a field before entering a term in the search builder box. Terms entered in the builder are automatically added to the search box. Note that the default Boolean operator is AND; choose OR or NOT from the pull-down menu if desired.

Combining Search Statements

Found on the Advanced Search screen, History holds your search strategies and results from your current search session. There are two ways to combine your search statements:

1. You may combine previous searches or add additional terms to an existing search using the pound sign (#) before the search number in the builder box.
   Examples:

   #2 AND #6

   #3 AND drug therapy

2. Click the search number to display additional options to add the search to the Builder, including Boolean operators OR or NOT.

Medical Subject Headings (MeSH) Indexing Tips

By using terms from the MeSH thesaurus, all articles on a given topic can be found regardless of the terminology used by the authors.

Specificity—Each article is indexed to the most specific MeSH terms available. For example, an article on acne is indexed under acne but not under skin diseases.

Near Match—Articles with no exact match are indexed to the closest related MeSH term, e.g., seminal vesiculitis to seminal vesicles, pseudoappendicitis to appendicitis, and nursing caps to clothing.

Two Terms—The most precise way to cover a topic may be to use two MeSH terms in combination, e.g., jejunitis to jejunal diseases and enteritis.

Textwords—It is assumed you will sometimes use text words to define a subject, e.g., tobacco smoke pollution (MeSH term) and passive (text word), to retrieve passive smoking.

Check Tags—Large-volume concepts are routinely "checked" for in each article by indexers. Check tags pinpoint specific age groups, males or females, humans or animals, publication types, etc.

Drugs—Drugs are indexed under the generic name, e.g., valium is indexed to diazepam.

Medical Specialty—There are separate terms for the medical specialty and the disease or organ (e.g., endocrinology is the specialty versus endocrine diseases or endocrine glands).

Neoplasms—Neoplasms are indexed to site and histologic type, e.g., adenocarcinoma of the colon is indexed to both colonic neoplasms and adenocarcinoma.

Relational Concepts—Some relational concepts cannot be indexed precisely, e.g., degrees of quality or quantity, specific time relationships, and primary versus secondary, except for neoplasms and general body positions. Try to experiment with text words for these concepts. Even then, you may not retrieve the relationship you wish.