To Find Articles, you must search a number of different databases, depending on the type of "social science research and theory" you are interested in or think likely to prove relevant. For a starter-list of the disciplines in question and the principal SPU indices to the literature in any one of them, see the boxes below. See also the subject guides at the University of Washington.
Academic Search Complete, Research Library Complete, Google Scholar, and others, cover many different fields of study, though not usually as well as any one of the discipline-specific indices listed above.
Note also that all EBSCOhost databases (the bulk of those listed above), and all ProQuest databases (Sociological Abstracts and Social Services Abstracts), can be searched simultaneously (though that is not necessarily the most effective way to search any given one of them). See the screenshots below:
Searching more than one EBSCOhost database simultaneously:
Searching more than one ProQuest database simultaneously: