If you are looking for a book that the Library only has in print, you can see if the book is in Google Books. Google Books offers portions of published books in full text. By law, they don't show the whole book, but there may be parts of the book you need available. And the book is fully searchable. https://books.google.com/
Open Access is a new emphasis by libraries and publishers to offer scholarly resources that are not under copyright and have "open access" by anyone. The Open Access Digital Theological Library offers books, commentaries, and open access journals freely to the public. This is a good place to check if you are having trouble finding the sources you need.
This Google custom search engine allows you to find full-text articles in hundreds ofreligious, open-access online journals and other periodicals. Search TJS either by using the quick search box above or by going to the TJSopens new windowWeb site. For more information about TJS, click opens new windowhere.