Enter SCIRUS for the most comprehensive scientific research tool on the web. Includes over 410 million scientific items. Search for journal content as well as scientists' homepages, courseware, pre-print server material, patents and institutional repository and website information. Includes also theses and dissertations.
Copernicus is both a repository and a completely open access geoscience publisher hosting several dozen titles. In fact, it is one of the oldest open access publishers, operating as such since 2001.
Probably the biggest, oldest and most active of the disciplinary repositories,arXiv now houses three-quarters of a million open access research publications and communications.
