How to use MeSH Qualifiers in a PubMed search string? I want to know how I combine a MeSH term with a qualifier. How do I create a search string on PubMed with it. The exact human readable question would be: All publications with MeshTerm "Locomotion" specified by qualifier "Physiology" and all publications with "Locomtion" not specified by any qualifier.

I am interested in the MeSH term Locomotion. As a search string I would write locomotion[mh]. The MeSH Browser tell me that one of it the qualifiers is physiology.

I can not find the word Qualifier somewhere in the PubMed help or in the available search fields.
I thought it is a synonym for MeSH Subheadings. But it doesn't look like.

Please see this two search queries which in my understanding should return the same number of results.


Even Wikipedia is on my side and say that Qualifier and Subheading should be the same.
MeSH terms are divided into descriptors (or main headings) and qualifiers (or subheadings). Each descriptor can have zero or more qualifiers. A qualifier cannot exist without being attached to a descriptor. 

The difference in the number of search results you have observed is because in your second search "locomotion/physiology" [mh] you are searching for entries which have the locomotion descriptor and physiology as a qualifier of the locomotion descriptor. In your first search "locomotion"[mh] AND "physiology"[sh] you are searching for entries with the locomotion descriptor and physiology as a qualifier to any of the MeSH terms attached to the entry.

For example PM28410594 is matched by your first search, but not your second.