VU Systematic Literature Reviews: Determine controlled vocabulary (subject headings)

In the paediatric population, do distraction techniques during immunisation result in less pain and anxiety?

Photo: James Gathany, Judy Schmidt, USCDCP

Subject heading search: Explode and major concept

Subject headings are a set of pre-determined terms (a controlled vocabulary) describing concepts within a specific database. The following course presentation demonstrates how to search using subject headings in various databases including how to broaden your search using the "Explode" concept and how to narrow your search and get fewer results using "Major Concept".




 Make an appointment with a librarian for help identifying relevant subject headings. 

Medical subject headings (MeSH)

 The example below shows a selection of MeSH terms


Concept 1


Paediatric population

during immunisation

Concept 2


Distraction techniques 

Concept 3


No treatment

Concept 4


Reduced pain and anxiety

MeSH Terms









internet-based intervention

cognitive behavioural therapy


virtual reality





pain threshold

pain perception

pain management

psychological distress


pain, procedural


This 3-minute video created by the NCBI is an excellent introduction to how to use MeSH to build a better PubMed query.

The National Library of Medicine. (2013, February 15). Use MeSH to build a better PubMed query [Video]. YouTube.

Complementary resources:

PubMed  automatic term mapping

You can identify relevant MeSHterms for your search by using PubMed's  Automatic Term Mapping to automatically search for other terms as keywords and match keywords with relevant MeSHterms. When you search PubMed by keyword,  click "History and Search Details" to see how PubMed ran your search behind the scene. Here you will find that the keyword immunisation is mapped to the MeSH term vaccination and immunity. 

Automatic Term Mapping will not happen if you apply the following search techniques:

  • search for a phrase in quotes 
  • use truncation 
  • search for a hyphenated term 
  • use a field tag  

Click here to watch the detailed video from the National Library of Medicine.