Since 1991 preprint versions of research papers have been shared online.
Publication of research manuscripts in a peer reviewed journal often takes weeks, months, and sometimes years. The need to to quickly distribute results within a scholarly community led researchers to distribute preprints. Preprints are manuscripts that have not yet been peer reviewed, and the early distribution allows authors to receive feedback from their peers.
Some of the larger preprint repositories:
These databases include many open access journals; look for the words 'Open Access' in your search results, or use the Open Access filter on the left menu of the search results page. They also show if the paper has an open access version available via the web e.g. from a university repository.
