These Library of Congress Research Guides are helpful when beginning research in various subject areas. You can search for the specific resources in Compass or request through Interlibrary Loan (ILL).
To find materials that are not held at Bowdoin, search MaineCat. You may then request materials using your name and campus ID. Still not finding the item you're looking for? Search WorldCat, and use "Check Availability @ Bowdoin" to fill out an ILL form. Another option is to search Google Books.