The Royal Society Digital Archive is easily the most comprehensive archive in science and contains some of the most significant scientific papers ever published. The development of the digital archive means that the Society's online collection now contains every paper ever published in the Royal Society's journals, including the entire back catalogue of Philosophical Transactions since 1665, the longest-running international science journal in the world.
It provides a record of some key scientific discoveries from the last 340 years — a few interesting examples:
Digital Archive FAQs
The Physical Sciences Journal Archive
The Biological Sciences Journal Archive
The Notes and Records Journal Archive
The Biographical Memoirs Archive (formerly Obituaries)