Proceedings of the National Academy of Sciences of the United States of America (PNAS) is the official
scientific journal of the
National Academy of Sciences, published since 1915. With broad coverage, spanning the biological, physical, and social sciences, the journal publishes "original research of exceptional importance", alongside scientific reviews, commentaries, and letters. In 1999-2009, the last period for which data are available, PNAS was the second most cited journal across all fields of science.
PNAS is published weekly in print, and daily online in
PNAS Early Edition.
