To search using the MeSH Database, click on "MeSH Database" under "More Resources".
When the next page opens, you can enter your search terms. When you type in your search terms, PubMed will show you a drop down box with additional words that are included in the MeSH Database.
When you choose your term, a new page will open which will show you more search builder options, such as subheadings, entry terms, and a "See Also" section. Below is an example of what pulls up when "aquatic biology" is picked. When you have chosen your search builder options, click on "Add to Search Builder" on the right side of the page. To view your results, click on "Search PubMed".
According to the NLM and PubMed, MeSH (Medical Subject Headings) "is the U.S. National Library of Medicine's controlled vocabulary for indexing articles for MEDLINE/PubMed. MeSH terminology provides a consistent way to retrieve information that may use different terminology for the same concepts."