Electronic Journals are arranged either by title or by subject by the University of Pennsylvania Library. Not all are free. Online Serials - A collection of almost 2000 titles arranged both alphabetically by title and also by subject from the Internet Public Library. The US All Media Jumpstation is a guide to more than 3,000 magazines, professional journals, trade, and consumer publications from Direct Contact Publishing. The directory is arranged by very specific subject categories.
Most publishing is, after all, a for-profit venture.
Below are listed free, or mostly free, sources. The Online Books Page from the University of Pennsylvania links to over 10,000 books. Project Gutenberg provides Etext editions a short time after they enter the public domain, which is 50 years more than the life of the author. Sites are thoroughly described. Purdue Virtual Reference Desk - Dictionaries, directories, maps and more.