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Searching PubMed using MeSH® Field Tags

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 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

Examples: eye [mh]
eye [majr]
  • 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.
Example: eye [mh] will retrieve citations indexed to:
 

Eye
Eyebrows
Eyelids
Anterior Eye Segment
Anterior Capsule of the Lens
Axial Length, Eye
Eyelids
Lacrimal Apparatus
Oculomotor Muscles
Pigment Epithelium of Eye
Posterior Eye Segment
Retina
Sclera
Tenon Capsule
Uvea

and all more specific terms underneath these in the hierarchy.
  • 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.
Examples: thromboembolism/pc [mh]
thromboembolism/prevention and control [mh]
toes/in [majr]
toes/injuries [majr]
  • 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