Most publishers provide TOC e-mail alerts/RSS feeds service for free. Some publishers also provide article alerts or search alerts which are similar to search alerts from article databases.
To set up alerts from individual journals, go to the publisher's website, register an account, and follow the instruction there.
Most databases provide search alerts which are based on the searches you have created. Every time the database is updated or on a schedule that you have defined, you will receive an alert. Your search strategy can be based on a topic, author, or journal title.
When choosing the appropriate databases to set up alerts, it is critically important to consider the update frequency of the database.
To set up a citation alert, click the title of the article to access the article record, then click Create Citation Alert.
Note: Alerting service is not available through Web of Knowledge All Databases Search.
For more information on auto-alerts types and how to set them up, consult this Auto-alerts instruction site.