The Free Medical Journals site links to a number of core clinical titles. Many offer automatic table-of-contents email alerts although not all content is free and some sites require registration.
These journals are open access but some do require registration.
Loansome Doc is a service offered via the National Library of Medicine, in which PubMed users can request full text articles from a partnering library. This service is suggested to health professionals and other individuals that are not affiliated with a health sciences library.