PubMed Tutorial from The Levy Library: Similar Articles Functionality
"Pearl Growing" or "Snowballing" is a search strategy that uses one good citation (the "pearl") to find additional relevant results.
PubMed's Similar articles functionality is designed to help you do just that.
PubMed uses a word-weighted algorithm to compare words from the Title, Abstract and MeSH headings of one record with all the citations in PubMed.
Similar Articles are then displayed in rank order of how closely they are related to the original citations according to the algorithm. This is different from the typical, reverse chronological display order of PubMed search results.
Look for the Similar articles link below each records on the search results page and on the full citation record for each citation in PubMed.