Mendeley is a free-web and desk-based reference manager and an academic social network.
Mendeley can help you to organize your research and to collaborate with other researchers. Mendeley has several special features, including syncing between Mendeley desktop and the Mendeley web account; always access from another computer, Iphone of Ipad; importing and organizing PDFs and sharing articles and PDFs with other Mendeley users.
From www.mendeley.com you can install the "Web Importer". The Web Importer is a browser plugin that allows you to select and import references into your Mendeley library while searching in systems like Scopus, Google Scholar, and PLoS.