When you click on a link to the left, it will take you to any instances of the journal, as it provided by the Libraries (in both electronic and physical formats). All the journals listed here are available online to some extent. Often, you'll see that the journal is available in multiple electronic resources, for example:
As you can see, in the above example Academic Search Complete has the most coverage, overall. Nevertheless, if you were looking for a very recent article, it would be best to use the Oxford University Press Link, as the other links do not have issues from the last 12 months.