Websites that I use frequently in my work:
The Editorial Freelancers Association is a national organization dedicated to the professional advancement of self-employed writers, editors, proofreaders, and the like.
The Board of Editors in the Life Sciences awards certification to qualified editors in the life sciences.
The National Library of Medicine houses everything from full-blown journal articles to abstracts to medical subject headings (otherwise known as MeSH) to info for the average citizen looking for medical information.
The Library of Congress has it all! Millions of books, periodicals, videos, microfilms; also special historical information, the U. S. Copyright Office, online exhibitions, and the National Recording Registry.