JSTOR provides access to scholarly articles in over 150 academic journals, as well as book chapters, published from the 1800s up to 1-8 years ago (more recent issues of a journal are generally not available in JSTOR due to publishers' embargoes). Coverage includes the arts, business, general science, the humanities, and social science.
Project MUSE offers full text of articles from 600+ current and historic scholarly journals, and book chapters, from major university presses. This database is good for research on literature and criticism, history, performing arts, cultural studies, education, philosophy, political science, gender studies, and more.
The National Bureau of Economic Research is a private, nonprofit, nonpartisan research organization dedicated to promoting a greater understanding of how the economy works. The NBER is committed to undertaking and disseminating unbiased economic research in a scientific manner, and without policy recommendations, among public policymakers, business professionals, and the academic community.
Working papers are freely-shared, pre-publication versions of articles. Authors share them in order to get feedback prior to submitting their work for publication.