Working papers are a way of finding the most current research in your field. Academics often release these drafts to share their research and elicit feedback before submitting the work to a peer-reviewed journal.
This database contains a number of working papers, including some from the National Bureau of Economic Research (NBER - www.nber.org). Under Search Options, change Publication Type to "Working Paper."
Among other things, this database contains working papers from the Social Science Research Network (SSRN). In the Source Type box, select "Working papers".