Google Scholar is described as 'Freely accessible web search engine that indexes the full text of scholarly literature across an array of publishing formats and disciplines. Released in beta in November 2004, the Google Scholar index includes most peer-reviewed online journals of Europe and' and is a popular academic research tool in the education & reference category. There are more than 25 alternatives to Google Scholar, not only websites but also apps for a variety of platforms, including iPhone, iPad, Windows and Linux apps. The best Google Scholar alternative is Semantic Scholar, which is free. Other great sites and apps similar to Google Scholar are WorldCat, ResearchGate, Scopus and Scinapse.