Google Scholar

Google Scholar is a freely accessible web search enginethat indexes the full text of scholarly literature across an array of publishing formats and disciplines. Released inbeta in November 2004, the Google Scholar index includes most peer-reviewed online journals of Europe and America’s largest scholarly publishers, plus scholarly books and other non-peer reviewed journals. It is similar in function to the freely available CiteSeerX andgetCITED. It is also similar to the subscription-based tools, Elsevier’s Scopus and Thomson ISI‘s Web of Science

https://scholar.google.com/