PubMed Subject Search: How it Works

A brief tutorial on how automatic term mapping and explosion enhance your PubMed search. For more educational materials on PubMed, see PubMed Online Training at www.nlm.nih.gov/oet/ed/pubmed/
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Transcript:
(music)
Here are the results for a PubMed search of gut microbiome allergy.
To see how PubMed interprets your search,
click Advanced, below the search box.
On the Advanced page, scroll down to History and Search Details.
Click the chevron in the Details column to
expand and show the search details.
PubMed maps your search terms with the Medical Subject Headings
(or MeSH), to match the terms you enter with the vocabulary
that indexers use to describe articles in PubMed.
You can see this mapping wherever the [MeSH Terms] tag appears in your Search Details.
The Translations section shows how PubMed interprets your different search terms.
In this search, PubMed maps “gut microbiome” to Gastrointestinal microbiome.
PubMed maps “allergy” to two MeSH terms:
Hypersensitivity, and Allergy and immunology.
PubMed may also include additional related
including synonyms, plural or singular forms, or British or American
variant spellings to enhance your search.
PubMed also includes more specific concepts encompassed by the mapped MeSH terms.
These concepts are not shown in your search details.
Let’s look at one example.
As mentioned, PubMed mapped your search term “allergy”
to the MeSH term “hypersensitivity.”
Return to the PubMed homepage to find the MeSH Database link
under the Explore menu.
You are now searching a thesaurus, or handbook of medical terms.
Search one concept at a time.
Let’s explore one of the concepts PubMed mapped from our search:
Hypersensitivity.
Your best matches appear at the top of your search results.
Notice that the first result is the MeSH term, “hypersensitivity.”
A brief scope note describes how the term is used in PubMed.
Click on the term to go to the full record.
The full MeSH record shows PubMed search options for this term.
These features are more fully described in the Medical Subject
Headings in MEDLINE/PubMed tutorial.
For now, scroll down to the bottom of the record,
which shows this MeSH concept in the context of broader
and narrower terms in the MeSH hierarchy.
If a MeSH term is mapped in your PubMed search,
any narrower terms are also included in the search.
This is called “automatic explosion.”
In this case, Hypersensitivity explodes to include terms like Drug Hypersensitivity,
Drug Eruptions, Environmental Illness, and Wissler’s Syndrome,
and all of the narrower terms beneath.
These explosions are not shown in your PubMed search details,
but you can see them here in the MeSH database record.
Try a search for antibiotic resistance soap
and view the search details.
Do all terms map?
PubMed maps antibiotic resistance to Drug resistance, microbial
and soap to Soaps.