Module 4: MeSH Search Techniques for Special Queries

When Is It Appropriate to Tag My Subject Terms?

Turn off Automatic Explosion

You may use a tag if you don’t want to include any narrower terms in your search. In this case, you would use the following syntax for no explosion, [mh:noexp]. Keep in mind that citations are indexed using the most specific term available, so turning off automatic explosion might eliminate relevant articles from your results.

For example, if you want to include the MeSH term eye in your search but none of its narrower terms, then you would search eye[mh:noexp].

Search details of eye[mh:noexp] showing that only the MeSH term eye is searched


  1. Which of these PubMed searches will retrieve results from the journal Blood?

  1. Which of these searches will tell PubMed to search school lunch as a phrase?

  1. How many narrower terms does the search Electrocardiography[mh:noexp] include?