Library Databases and search engines
DOAB: The Directory of Open Access Books covers free, full text, quality controlled academic and peer reviewed books.
DOAJ: The Directory of Open Access Journals covers free, full text, quality controlled scientific and scholarly journals.
BASE: Bielefeld Academic Search Engine is a search engine especially for academic open access web resources. BASE is operated by Bielefeld University Library.
Open Science Directory: A search tool from EBSCO for open access journals and journals in special programs for developing countries.
ROAD: Directory of Open Access scholarly Resources provides free access to a subset of ISSN bibliographic records identifying online scholarly resources available in Open Access: journals, conference proceedings and academic repositories.
Web of Science®: It is part of the Web of Knowledge platform of Thomson Reuters, and it is responsible for citations analysis.
Academic Search:It is a free service developed by Microsoft to help researchers, professors, students and professionals to find academic content quickly and easily.