American Heart Association Professional Journals (Arteriosclerosis, Thrombosis, and Vascular Biology; Circulation; Circulation Research; Hypertension; Stroke)

American Literature on the Web - Electronic Journals and Collections (Akihito Ishikawa)

BioMed Central (Biomedical research, peer-reviewed)

Early Modern Literary Studies 

eScholarship Repository (peer-reviewed articles) (California Digital Library)

FindArticles.com 

HighWire Press (peer-reviewed journals)

Internet Library of Early Journals : A digital library of 18th and 19th Century journals

Journal of Visualized Experiments (video articles)

JournalJunkie (podcasts for medical practitioners)

New Jour: Electronic Journals and Newsletters (Ann Okerson & James O'Donnell)

Open Access Journals

Open Access Journals in Education

Proceedings of the National Academy of Sciences

Public Library of Science (peer reviewed)

PubMED and PubMed Tutorial
(over 15 million citations for biomedical articles from MEDLINE
and additional life science journals back to the 1950's)
(National Library of Medicine)

PubMed Central (Life Science Journals, peer-reviewed)

Scholarly Journals Distributed Via the World Wide Web (U of Houston)