Searching PubMed using MeSH^® Field Tags

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Untagged terms that are entered in the PubMed search box are automatically mapped to the MeSH vocabulary when a match is found. However, you may choose to search the MeSH headings specifically using search field tags (also called qualifiers).

Note: Searching with MeSH subject terms excludes in process and publisher-supplied citations and others that do not (or do not yet) include MeSH subject terms.  

MeSH headings [MH]

• MeSH headings can be qualified using two search field tags:

                        [mh]     to search a MeSH heading
                        [majr]   to search a MeSH heading that is a major topic of an article

• PubMed automatically searches the MeSH headings as well as the more specific terms beneath that heading in the MeSH hierarchy. This is known as the explosion feature.

• To turn off automatic explosion of MeSH headings, use one of the following tags:

                         [mh:noexp] or [majr:noexp]

Example:

eye [mh:noexp]

This retrieves citations indexed with the term, Eye – but not necessarily indexed with the terms beneath that heading in the MeSH hierarchy.   Remember that indexers use the most specific MeSH heading to describe the subject of a journal article.

Subheadings [SH]

• A list of subheadings can be found in PubMed's Help.
• MeSH specialists and indexers determine which subheadings may be used in combination with each MeSH heading.   These combinations may change over time.
• For searching, attach subheadings to MeSH headings using the format: MeSH heading/subheading.  
• Two-letter abbreviations for subheadings or the full subheading name may be used.

• Only one subheading may be attached to a MeSH heading at a time.   To attach multiple subheadings, combine each MeSH/subheading combination with the OR Boolean operator or use the MeSH Database, which allows multiple subheadings to be selected.

Example:	To search for citations where the main topics are about the prevention and control or diagnosis of thromboembolism, enter:
	thromboembolism/pc [majr] OR thromboembolism/di [majr]

• For a MeSH/subheading combination, PubMed always explodes the MeSH term and also searches the subheading and its grouping if there is one.   You cannot explode a MeSH heading and not also explode the attached subheading.

Example:

polysaccharides/ae Retrieves citations indexed with any of the polysaccharides with any of these subheadings:    ae (adverse effects) po (poisoning) to (toxicity)

Note:   polysaccharides/ae [mh:noexp] turns off both the MeSH heading explosion and the subheading explosion.

Unattached subheadings

•  You may also choose to search a MeSH heading and a subheading combination using the AND Boolean operator and the subheading field tag of [sh].  This may be done when you want to search for a subheading concept that cannot “legally” be attached to the MeSH heading you are also searching.

Example:

hypertension [mh] AND toxicity [sh]

• To turn off the subheading grouping, use the tag [sh:noexp].   Do this only when using an unattached subheading.

Example:

finger injuries [mh] AND surgery [sh:noexp]

PubMed’s Help includes:

Subheading list

See also:

Subheading (Qualifier) Hierarchy