There are thousands of quality online resources to explore (and about a million more of less-than-quality blogs/websites). These are just a selection of excellent sites and online journals, and for the most part feature collections of archived digitized publications. If you are unsure of what you can safely cite in your research paper, ask a Librarian or your Professor.
American Radio History - Access thousands of digitized historic journals on radio, broadcasting, and sound recording.
Domitor Journals Project - Domitor, an association of the International Society for the Study of Early Cinema, offers digital collections of international periodicals relevant to early cinema studies.
Literature Index - Originally in print, FLI Online contains approximately 700,000 citations to articles, film reviews and book reviews published between 1976-2001.
Margaret Herrick Library Digital Collections - The library of the Academy of Motion Picture Arts and Sciences presents a curated selection of materials from the library's extensive holdings on motion picture history. Items include correspondence, photographs, sheet music, scrapbooks, lobby cards, movie ephemera, books, film magazines and industry publications. The collections also provide access to publications of the Academy of Motion Picture Arts and Sciences dating back to the founding of the organization in 1927.UCLA's journal of Cinema and Media Studies.
Mediascape - UCLA's journal of film and media studies from the School of Film, Television and Digital Media.
Media History Digital Library - A collection of digitized works on film, broadcasting, and recorded sound in the public domain (free!).
Motion Picture Script Database - Film script holdings of seven Los Angeles area collections: the Academy of Motion Picture Arts and Sciences; the American Film Institute; the Frances Howard Goldwyn Hollywood Regional Library; the University of California, Los Angeles; the University of Southern California; the Writers Guild of America, West; and the Warner Bros. Archives at University of Southern California's School of Cinematic Arts.
MOVIE: A Journal of Film Criticism - Critical research on film and television. This journal is a joint venture between the Universities of Warwick, Reading, and Oxford.
ScreenSite - An aggregate of online journals, magazines, and blogs on the study of film, television, and related media. Produced by the Telecommunication and Film Department of the University of Alabama in partnership with the Society for Cinema and Media Studies.