From the Windows Live Help file:
Windows Live Academic Search accesses content feeds from several publishers in the Computer Science, Physics, and Electrical Engineering areas. Academic Search works with CrossRef to facilitate cross-publisher searching. Publishers include ACM, American Institute of Physics, American Physical Society, Blackwell Publishing, Elsevier Science, IEEE, Institute of Physics, John Wiley and Sons, Nature, Taylor and Francis, and many others.
To access Windows Live Academic Search - http://academic.live.com/.
You can also open live.com, enter a search term and execute the search, then click "Academic" to try your search across academic sources.