If you are finding too few relevant references then you may need to look at expanding your search.
You can use the following features to help you identify further articles which may be of interest:
You can also experiment with broadening your search terms and adding synonymous terms into your search strategy.
Of course, it may just be that there is very little written on your topic! Ask a librarian for advice if you require further help with your search.
When looking at the abstract page of a record, you may see that PubMed suggests Similar Articles to the article that you are looking at.
PubMed uses a word-weighted algorithm to compare MeSH headings and words from the Title and Abstract of each citation in PubMed. The best matches found by this algorithm for each citation are then stored and recommended as Similar Articles.
Some citations will not yet have Similar Articles links because they have not yet gone through the algorithm process. For more information see PubMed's detailed guide to how Similar Articles are computed.
PubMed offers cited reference searching which can be a useful way of expanding the list of references you have found, by finding more recent articles that have cited the article you are looking at. You can view Cited By links by looking at the bottom of a reference when your results are displayed in abstract view. The full record of an individual article also contains a list of Cited by articles.