Google Scholar, Web of Science, and Scopus: A systematic comparison of citations in 252 subject categories

作者：

Highlights：

• Google Scholar found nearly all citations found by WoS (95%) and Scopus (92%), and a large amount of unique citations.

• About half of Google Scholar unique citations are not from journals. A significant minority (19–38%) are not in English.

• Google Scholar unique citations have, on average, a much lower scientific impact than citations also found by WoS/Scopus.

• Spearman correlations of citation counts between Google Scholar and WoS/Scopus are strong across all subjects (0.78–0.99).

摘要

•Google Scholar found nearly all citations found by WoS (95%) and Scopus (92%), and a large amount of unique citations.•About half of Google Scholar unique citations are not from journals. A significant minority (19–38%) are not in English.•Google Scholar unique citations have, on average, a much lower scientific impact than citations also found by WoS/Scopus.•Spearman correlations of citation counts between Google Scholar and WoS/Scopus are strong across all subjects (0.78–0.99).

论文关键词：Google Scholar,Web of Science,Scopus,Bibliographic databases,Academic search engines,Coverage,Citation analysis,Unique citations,Citation overlap,Bibliometrics,Scientometrics

论文评审过程：Received 15 August 2018, Revised 30 August 2018, Accepted 3 September 2018, Available online 5 October 2018, Version of Record 5 October 2018.

论文官网地址：https://doi.org/10.1016/j.joi.2018.09.002