Recursos académicos de acceso libre Springer Nature The Lancet Wiley Online Library PMC Annals of Internal Medicine PNAS British Medical Journal Cochrane Cambridge University Press The New England Jorunal of Medicine Journal of American Medial Association Sage Journals Plos Elsevier Oxford Academic Journals Emerald Taylor & Francis Online Jstor American Chemical Society American Society for Microbiology IOP Publishing Repositorio CONACYT COVID-19 Salud Colectiva Observatorio social del Coronavirus