For the next 45 days we have access to all of the content available from ProQuest that we do not currently own or subscribe to. The URL for the trial is http://tinyurl.com/p6vpp2o (be patient, it takes a while for the page to load.) You'll notice some resources appear under more than one category.
These resources include Historical Newspapers, British Periodicals, History Vault collections like Slavery and the Law and Politics and Society 1960-1975, and many, many others. If any of these resources support the research that you or your students are doing, it is important that you let me know. Please email me with your feedback.