In CQ Researcher and SIRS Researcher, it's easiest to select an issue from their list of issues.
In OneSearch, try searching for your issue and add the term 'conservative' or 'liberal' (I would start with one at a time) to see what articles appear. Please be aware that you might find more articles written by one group explaining why the 'other' perspective is wrong when you search this way, but publication titles and articles aren't searchable in databases by viewpoint so this is the closest you can do.
When using the websites on this page and others you may find, it's always useful to check the "About Us" page and confirm your findings in other sources.
Contact a librarian if you get stuck! We're here to help: