PubMed

MeSH or Medical Subject Headings is the controlled vocabulary thesaurus PubMed uses to index citations. Searching the MeSH database from PubMed is easy, but requires you to navigate to and from the MeSH website. You can use the MeSH database to find MeSH terms, including Subheadings, Publication Types, Supplementary Concepts and Pharmacological Actions, and then build a PubMed search.

To get to the MeSH database from the PubMed homepage, scroll down to  the middle of the page and under "Explore" click on "MeSH Database"

MeSH is organized in a tree like structure with headings and subheadings. 

MeSH is built to interact smoothly with the PubMed database. You can therefore use the search builder tool in MeSH to create a PubMed search with the subject terms you find. To build a PubMed search from MeSH:

1. Run a search in the MeSH database.  An autocomplete feature is available from the search box
2. Search results are displayed in relevance-ranked order, therefore, when a user’s search exactly matches a MeSH Term, that term is displayed first.
3. Select terms using the check boxes or click the MeSH term from the summary display or choose full from the display format menu to view additional information and search specifications, such as subheadings, restrict to Major MeSH Topic, or exclude terms below the term in the MeSH hierarchy.
4. Click "Add to search builder" in the PubMed search builder.
5. You may continue searching and including additional terms to the PubMed search builder using the "Add to search builder" and Boolean pull-down menu.
6. When you are finished, click "Search PubMed."

taken from https://pubmed.ncbi.nlm.nih.gov/help/#using-mesh-database 

• There is a lag time for items to be tagged with MeSH terms in the PubMed database. If you are wanting the most recent research on a topic, therefore, you may want to consider doing a combined keyword and MeSH search.
• MeSH has changed and evolved over the years. Where it says "Year Introduced"  refers to when the term was added to MeSH. If more than one year is shown, the term was available for indexing back to the earliest year noted. Articles are indexed using the vocabulary in place at the time of indexing.