Are there any search engines that have scholarly materials?
There are a some sites on the web that list scholarly articles, papers, and
web sites but these do not
cover every subject or every topic.
As previously mentioned, for full text articles try: http://highwire.stanford.edu, http://www.doaj.org, or http://www.biomedcentral.com. Remember the articles in these sources are primarily in the life sciences.
There is also Google Scholar at http://scholar.google.com which lists an occasional full text article among the abstracts and references and Ingenta.com at http://www.ingentaconnect.com which lists no full text articles, but does have references and summaries.
Then there is Infomine at http://infomine.urc.edu which lists scholarly web sites by subject and which offers a search engine as well.
Remember, if you have any questions at all about anything you find on the web, please remember to ask a librarian.