Discovery searches multiple resources, including the catalog and many databases, all at one time. Want better results? Try using one of Discovery's limiters, located in the left-hand column of your search results page.
You can also search in the catalog. If a URL link appears in a record, the book is available electronically. Records for print-only books will display a call number and the location "stacks." If you need help locating a book, consult a stacks directory near the elevators or ask a librarian.
Note that Discovery also searches the Hathi Trust Digital Library, a collection of 11 million digitized books from more than 50 major research libraries. Most of the books are out of copyright and therefore older, so this is a great place to search for primary sources.