A database for locating both modern and historical research (back to ~ 1890). Be sure to "narrow by discipline." When you first arrive at JSTOR, scroll down the page and check the box labeled "Political Science".
Multidisciplinary database. Academic OneFile - like Academic Search Elite - crosses over many disciplines. Be sure to click on the "Advanced" option at the top of the page. Then consider limiting your search by "Document Title", "Abstract", or "Subject". To focus on research be sure to choose the "Peer Reviewed Journals" option before or after you search.