Google Scholar - Google Scholar is a freely accessible web search engine that indexes the full text of scholarly...
Scopus - Scopus is a bibliographic database containing abstracts and citations for academic journal articles.
Google Custom Search - Google Custom Search enables you to create a search engine for your website, your blog, or a collection of websites.
ACI Scholarly Blog Index - ACI is revolutionizing the way people conduct research by enabling them to find the content they’ve...
ResearchGate - Access scientific knowledge, and make your research visible
Scinapse - Scinapse is a free, nonprofit, Academic search engine for papers, serviced by Pluto Network.