Electronic Tables of Contents (eTOCs): Individual table of contents alerts with full-text links can be delivered to you from specific journals or from multiple journals through PubMed (and other databases).
PubMed's MyNCBI: PubMed personal account. You can specify that PubMed run previously saved searches. MyNCBI will deliver new articles from your searches to your email or an RSS reader.
Ovid Personal Account: Similar to PubMed's MyNCBI, but for the Ovid databases.