Many databases allow you to set up alerts so that you're notified whenever an article is cited, whenever an article is available that meets your search criteria, or whenever a new journal becomes available. For these services, you need to have an account/profile in the database.
Rich Site Summary (also known as Really Simple Syndication) or RSS is a type of web feed that will deliver updates for online content that you select in a standardized format. You will need a downloadable or web-based feed reader or news aggregator to read and manage your feeds.
Several types of alerts or RSS feeds are available, including:
The following popular science databases have been identified as having alerts or RSS feeds available. This is not a comprehensive list, so check your favorite databases and resources for similar language on setting up alerts or RSS feeds.