Most bibliographic databases have the capability to provide you with citations to newly-added publications on subjects of interest to you. PubMed is no exception. To get started with automated current awareness, take a look at the information put together by UCSF librarians. On that page, there's also a link to an automated online tutorial developed by the NaNNLMNational Network of Libraries of Medicine that's worth looking at. It takes only about 4 minutes.