It's tempting to turn to the internet for all our information needs but only a tiny fraction of published research has been digitized and much of the good stuff is buried by junk. Don't despair!
Books are incredibly detailed sources of information. Finding one good book often provides several good leads.
Beowulf and the Grendel-Kin by 
Marie de France Poetry by 
Memory and Confession in Middle English Literature by 
Medieval Sign Theory and Sir Gawain and the Green Knight by 
Chaucer's People: Everyday Lives in Medieval England by 
Desire in the Canterbury Tales by 
The Comic Mode in English Literature by Knowing the difference between search fields helps you dig deeper into a database to find relevant information.
Keyword: searches anywhere and everywhere for the search term. You get lots of results but fewer will be relevant to your research.
Subject: searches only in the subject headings for the term. You will get results where your search term has been described as one of the main subjects of an item, meaning fewer results but much more relevant sources of information.
