If you go to the library home page (www.usd.edu/library), you should see five tabs across the middle of the page.  Select the Books & More tab.  From there, you can select Advanced Search (this should be in red letters).  You can search by title, author, subject, or word by selecting the drop down box to the appropriate category.  For example, if I wanted to search by education, I could type in education in the search box and select the subject word/s from the drop down box.