If you want to research PubMed abstracts this is a great video to watch.
Searching PubMed Like an Expert: Using MeSH Terms
https://www.ncbi.nlm.nih.gov/pubmed/
If you think you are going to be using PubMed you might want to register for an account so that you can save searches and more. I registered this week and it is free.
@Hopeoftheflame had a class in medical research for librarians this past summer and she tells me that MeSH terms are the way to do this.