Northwestern Libraries subscribes to thousands of journals, and has access to millions of books. We still don't have everything, though, but we can get it for you (for free!) via Interlibrary Loan (ILL). In other words, never pay for anything for your research!
As an undergraduate at Northwestern, you have a librarian for the subject you're studying. They are all listed on the library website.
After you graduate and are in school for your chosen health profession, you will have a librarian for your specific field as well. For example, here are the librarians at Galter Health Sciences Library.