This multi-disciplinary search engine, from Germany's Bielefeld University Library, searches academic and related web resources.
The basic search screen allows the user to check a box to search for additional word forms. The advanced search has a robust list of search options: by document type, country, and publication year, plus six options for each search box. The "Check this title in Google Scholar" link is a helpful way to find the resource in a particular library collection when searching via a campus portal.
For more information: http://www.base-search.net/about/en/index.php