Another great resource from research whiz Marcus Zillman over at LLRX – Academic and Scholar Search Engines and Sources – An Annotated Link Compilation. In Mr. Zillman’s own words:

This new guide focuses on the latest and most significant academic and scholar search engines and sources. With the constant addition of new and pertinent information released online from every sector, it is very easy to experience information overload. A real asset in responding to the challenges of so much data is to apply techniques to identify and locate significant, reliable academic and scholarly information that resides in both the visible and invisible web. The following selected academic and scholar search engines and sources offer a wide range of actionable information retrieval and extraction sources to help you accomplish your research goals. 

There’s a metric tonne of good stuff in his list. Have at it!