What is MeSH?
MeSH (Medical Subject Headings) are standardized keywords that you can look up in the MeSH Database. The majority of articles in PubMed (over 90%) have been assigned MeSH terms to provide information on the content of the articles. MeSH terms are manually assigned by indexers of the NLM (National Library of Medicine).
Why use MeSH?
By using MeSH terms in your search, the various synonyms of a term are automatically included in the search query.
Example: In literature the concept of 'cancer' can be described in various ways: cancer, cancers, tumor, tumour, neoplasms etc. If you were to search using the word 'neoplasms' only, you would miss articles. If you search with the MeSH term 'neoplasms', you will find articles on this subject no matter which words were used to describe this concept.
Using MeSH alone is not enough. Why?
- You will not find the latest articles
MeSH terms are manually assigned to articles. As this takes time, the latest articles will not have been assigned any MeSH terms yet and therefore will not appear in your search results if you only use MeSH terms in your search.
- There is no appropriate MeSH term
Sometimes there is no MeSH term for the concept you are interested in. In that case, it is important to search (additionally) for relevant words in the title and abstract, for instance.
Demo: Zoeken met MeSH (3:03)
Watch this video from Laupus Health Sciences Library (East Carolina University) for a demo on the MeSH database.
To search PubMed using the selected MeSH terms, click on 'Search PubMed' after selecting the MeSH terms in the MeSH database (with 'Add to Search Builder').
MeSH - Extra information
The MeSH Database provides additional information on all MeSH terms
(see the Raw Foods example below):
- Definition of a MeSH term
- Entry terms: similar words (synonyms) that are grouped together under the same MeSH term
- The ordering of related MeSH terms; MeSH terms are hierarchically ordered in an inverted tree structure. A MeSH term can belong to multiple categories.
- Closely related terms (if present) under See Also
There are several ways to search more specifically with a MeSH term
(see the Intensive Care Unit example below):
- Subheadings are aspects or contexts to restrict a MeSH term.
For instance, if you are looking for articles about the supply of resources in ICUs, you can tick the subheading supply and distribution and search with "Intensive Care Units/supply and distribution"[MeSH].
- With Major Topic you will only find articles where the MeSH is the main topic.
For example, searching with "Intensive Care Units"[Majr] you will not find articles where this topic is covered to a lesser extent.
- No Explode
When searching with a MeSH term such as "Intensive Care Units"[MeSH], by default you will also search with the more specific MeSH terms that are located under this term in the tree structure: Burn Units etc.
If you do not want to include these more specific terms, you can turn this off by checking 'Do not include ...'. You will then be searching with
"Intensive Care Units"[MeSH:NoExp], where NoExp means no explode.
Tip: compare the number of results of the four searches mentioned above.
In the MeSH database you can also find Pharmacological Action terms. This is a special type of MeSH that allows you to search for pharmacological action, e.g. "Serotonin Uptake Inhibitors"[Pharmacological Action]. On the information page you can see which drugs are included.
If you would only search with "Serotonin Uptake Inhibitors"[MeSH], then you would miss articles about Prozac for instance ("Fluoxetine"[MeSH]).
A supplementary concept is a preliminary stage of a full MeSH term. Supplementary concept is often used for rare diseases and drugs, e.g. Moderna's COVID-19 vaccine: "mRNA-1273 vaccine" [Supplementary Concept]. It is possible to search with this term and on the information page you can see under which MeSH this Supplementary Concept term is grouped.
The last category of terms are publication type terms. These are used to indicate the publication type, e.g. "Randomized Controlled Trial" [Publication Type].