For Northwestern affiliates, to authenticate via Northwestern's databases to find the full text, you can go to Edit -> Preferences and click on Find Full Text.  To sync with library databases, add the following:

Open URL Path: http://resolver.library.northwestern.edu/nwu

Authenticate URL: http://turing.library.northwestern.edu/

Note that Find Full Text works much better from on-campus. For off-campus users, connect to the virtual private network (VPN) to simulate being on campus.