Google Scholar

Google Scholar is a freely accessible web search engine that indexes the full text or metadata 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 America's largest scholarly publishers, plus scholarly books and other non-peer reviewed journals. While Google does not publish the size of Google Scholar's database, third-party researchers estimated it to contain roughly 160 million documents as of May 2014 and an earlier statistical estimate published in PLOS ONE using a Mark and recapture method estimated approximately 80-90% coverage of all articles published in English.

Google Scholar is similar in function to the freely available CiteSeerX and getCITED. It also resembles the subscription-based tools, Elsevier's Scopus and Thomson Reuters' Web of Science.

History

Google Scholar arose out of a discussion between Alex Verstak and Anurag Acharya, both of whom were then working on building Google's main web index. Their goal was to "make the world's problem solvers 10% more efficient" by allowing easier and more accurate access to scientific knowledge. This goal is reflected in the Google Scholar's advertising slogan – "Stand on the shoulders of giants" – taken from a quote by Isaac Newton and is a nod to the scholars who have contributed to their fields over the centuries, providing the foundation for new intellectual achievements.