Evidence of open access of scientific publications in Google Scholar: A large-scale analysis

Highlights：

• 55% of the documents covered by Web of Science from 2009 and 2014 are freely available in some form from Google Scholar.

• 23% of documents are available from the publisher, 17% from repositories, and 40% from other sources, mainly ResearchGate.

• Many publishers still do not declare a clear user license in CrossRef, difficulting the identification of OA types.

• OA levels are higher in the Natural and Health sciences, and lower in Social Sciences, Engineering, and Arts & Humanities.

• OA levels are higher for publications produced in Europe, USA, and Brazil (36–50%), than in Asian countries (18–36%).

摘要

•55% of the documents covered by Web of Science from 2009 and 2014 are freely available in some form from Google Scholar.•23% of documents are available from the publisher, 17% from repositories, and 40% from other sources, mainly ResearchGate.•Many publishers still do not declare a clear user license in CrossRef, difficulting the identification of OA types.•OA levels are higher in the Natural and Health sciences, and lower in Social Sciences, Engineering, and Arts & Humanities.•OA levels are higher for publications produced in Europe, USA, and Brazil (36–50%), than in Asian countries (18–36%).

论文关键词：Academic publishers,Academic search engines,Academic social networks,Creative commons,CrossRef,Google Scholar,Institutional repositories,Open access,Open research metadata,ResearchGate,Self-Archiving

论文评审过程：Received 16 April 2018, Revised 13 June 2018, Accepted 30 June 2018, Available online 24 July 2018, Version of Record 24 July 2018.