[Preprints in biomedicine: alternative or complement to the traditional model of publication?].

The peer-review system has allowed the quality control of the manuscripts submitted for publication to scientific journals for over three centuries. However, due to its relative slowness and other drawbacks, some researchers, mainly in the areas of Physics and Mathematics, started some decades ago to propagate, by electronic means, manuscripts not yet submitted to a journal for formal publication. The dissemination of this practice led to the establishment of permanent repositories like ArXiv, to which preprints can be sent to be published whitou charge, allowing also the search and download of the works they contain with no payment required from the reader.