PubMed is the National Library of Medicine's online service for searching the MEDLINE database and additional biomedical and life sciences literature. It is one of the most up to date, comprehensive and powerful ways for finding scholarly literature in biomedicine.
To start, go to PubMed and try doing a simple search as shown below:
When you first do a search, the results will automatically be sorted by Most Recent, so newest articles at the top. Change the sorting to Best Match. This will bring the most relevant articles to the top.
Use Filters in PubMed to narrow a search by particular attribute like article type or publication year. Watch the following video to learn more (note that the video is 2 minutes in length and will automatically jump into another video after it finishes).