Scopus allows the creation of email alerts and RSS to keep you up to date with the latest citations and abstracts. You can create a Search Alert, a Document Citation Alert, or an Author Citation or New Document Alert.

To create Alerts, you need to register for a personal account. There is no limit on the number of alerts you can create.

To set up Alerts (citation, journal & search alerts are available) in Web of Science.

First you must sign in to the database 
After you do a search, click on "Create Alert/RSS."
Give the alert a name and description (optional), check the box next to “Send me email alerts” (if you want email alerts) and make any other choices you wish.
Click on “Save Your History to the Server.” It’s at this point you have the choice of sending the search to an RSS feed if you prefer.

JournalTOCs is the largest, free collection of scholarly journal Tables of Contents (TOCs):

more than 32,000+  journals from 3333 publishers
Alerts you when new issues of your followed journals are published - including their table of contents.
Create an alert:
Register with the website (top right hand corner) and sign in
Search for journals and tick any you would like to follow; e.g. 
This automatically adds it to your list of Followed Journals

Click Followed Journals under your login to view your followed journals

To be emailed when new issues are published, make sure to tick the checkbox  ​
 

A Table of Contents (TOC) service alerts you each time a new issue of a journal is published. Links to full-text articles are sometimes provided.

You will need to register with the database or journal. This is usually free.

Some major publishers with TOC alerts include:

Cambridge Journals Online
This is the online content delivery service for Cambridge University Press’s collection of nearly 200 leading journals across the sciences, social sciences and humanities.
Oxford Journals
Provides full-text online access to electronic journals published by the Oxford University Press. Disciplines covered are humanities, social sciences, and the sciences.
ScienceDirect
Register on the ScienceDirect homepage, and then set up alerts for the journals you want to keep track of.
SpringerLink
Provides the full text of over 1000 scientific journals. SpringerLink provides online information services for scientific, technical, and medical (STM) books and journals.
Taylor & Francis Online
Find the journal you are interested in and simply click "Alert me" to choose emails or an RSS feed.

Google Scholar will allow you to create alerts for searches, citation, authors and topics. 

You can set alerts without registering but to save your searches you'll need to register with Google Scholar

For Search Alerts, simply click the button on the screen after you get your search results

For Citation Alerts click the cited by button first, then Create Alert

For Author Alerts Click the Author name and if they have a Google Scholar Citations Profile, Click Follow.

For Topic Alerts Click this link and fill in your topic query