Doctor of Nursing Practice (DNP) Guide

Medical Subject Headings (MeSH) are the National Library of Medicine's controlled vocabulary. A controlled vocabulary is a specified, pre-determined collection of terms (about 30,000 in this case). They are used to catalog and index the article records in PubMed. MeSH terms are arranged into tree structures and are updated every year to include new developments. You cannot make up or add your own MeSH terms, you can only use one of the pre-existing terms. MeSH terms are found in their own database, MeSH Database.

Why use MeSH?

MeSH are a retrieval tool that can help increase the accuracy and completeness of a search. MeSH cannot be made up and must be looked up in the MeSH Database. Each article in PubMed is indexed with a handful of these terms. When searching on subject headings, all articles tagged with that heading will be retrieved. You can use MeSH terms in your search query to help retrieve more relevant results.

MeSH vs. Keywords

It is considered best practice to use a combination of keywords and MeSH terms in your search. The most recent articles in PubMed do not have MeSH terms attached to them yet, and it can take up to six months to be tagged with MeSH. To ensure your search is all-encompassing, combine your MeSH terms with keywords using the boolean operator OR.

For example: (child* [tiab] OR "Child"[Mesh])

This search query will bring back citations with the MeSH term obesity, as well as any citations where obesity is mentioned in the title or abstract. Check out Limiting Field Codes for more details on how to limit keywords to only show up in the title or abstract.

1. If you are in the main PubMed search screen, click on "MeSH Database" as seen above. If you are on any other page in PubMed, scroll down to the very bottom of your screen.

2. This will redirect you to the MeSH database, where you can locate your MeSH terms. Type your term into the Search box and hit the search icon. Results will default to returning Subject headings by best match. You might have to scroll through to find the one that best fits what you're searching for.

3. Results will default to returning Subject headings by best match. You might have to scroll through to find the one that best fits what you're searching for. Once you found a MeSH term that best fits your keyword/topic, click on it. 

4. Once you have identified the MeSH term that best fits your keywords/topic, you will want to pay attention to a few features in MeSH Database.

• Entry Definition - Each MeSH entry will have a quick definition and the year the term was introduced.
• Entry Terms - The entry terms show you a quick overview of additional keywords. These are worth taking a look at because you might find additional synonyms that you can use for your search strategy.
• MeSH Hierarchy - MeSH is organized in a hierarchy. Each entry will show you where this MeSH term falls in the hierarchy.
  • Note: You will want to pay attention to this because sometimes the terms indexed below the MeSH term you searched on might not be appropriate for your search. Other times you might find that the MeSH term above the term you searched on might be a better fit. 
• Additional Searching Options - These two options help restrict how you search on a MeSH term
  • Major Topic will retrieve references that have this subject heading as their main topic. This will find fewer results, but with higher relevance.
  • Not including MeSH terms found below this term will help you search on just that subject heading without blowing up the search the include subject headings below that might not be appropriate

5. To search on your MeSH term, you can click "Search PubMed" and you will be redirected to PubMed. The results returned will be articles that have been tagged with the MeSH term that you selected.

Note: If you will be adding more than one MeSH term, it might be a better idea to click "Add to search builder". This will display your selected MeSH in the PubMed Search Builder. Here you can continue to add MeSH terms using the Boolean operator of your choice. In the example below, the MeSH term for child was previously added. This is now demonstrating how to add a secondary MeSH term for adolescent.

6. After you have your searches of subject headings and keywords, you have to combine your searches together.

Tip: For more details on combining searches, look at our Searching Tips section.

You have now completed a search that includes PubMed's Medical Subject Headings!

When adding using MeSH terms, there are three different options in which you can use the headings. 

• As is - Unless another option is selected, this is the default. It retrieves all articles indexed with that MeSH term as well as any MeSH term below this hierarchy if any. 
  • Ex. "Child" [Mesh]
• Major Topic - This will retrieve references that have this subject heading as their main topic. This will find fewer results, but with higher relevance.
  • Ex. "Child" [Majr]
• Not including MeSH terms found below this term will help you search on just that subject heading without blowing up the search the include subject headings below that might not be appropriate
  • Ex. "Child"[Mesh:NoExp]

Subheadings are an advanced tool that provide more detail for your search. They can help narrow your subject headings to cover areas such as therapeutic use, adverse effects, analysis, pharmacology, and much more. 

PubMed defaults to not having any subheadings. You have the option to narrow your results further by selecting specific subheadings from the list. However, this can be very restrictive and may cause you to miss relevant references. Use with caution. Also note that subheadings will vary from subject heading to subject heading. Some MeSH terms might not have any.