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  • × author_ss:"Ortega, J.L."
  1. Delgado-Quirós, L.; Aguillo, I.F.; Martín-Martín, A.; López-Cózar, E.D.; Orduña-Malea, E.; Ortega, J.L.: Why are these publications missing? : uncovering the reasons behind the exclusion of documents in free-access scholarly databases (2024) 0.01 
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    Abstract
    This study analyses the coverage of seven free-access bibliographic databases (Crossref, Dimensions-non-subscription version, Google Scholar, Lens, Microsoft Academic, Scilit, and Semantic Scholar) to identify the potential reasons that might cause the exclusion of scholarly documents and how they could influence coverage. To do this, 116 k randomly selected bibliographic records from Crossref were used as a baseline. API endpoints and web scraping were used to query each database. The results show that coverage differences are mainly caused by the way each service builds their databases. While classic bibliographic databases ingest almost the exact same content from Crossref (Lens and Scilit miss 0.1% and 0.2% of the records, respectively), academic search engines present lower coverage (Google Scholar does not find: 9.8%, Semantic Scholar: 10%, and Microsoft Academic: 12%). Coverage differences are mainly attributed to external factors, such as web accessibility and robot exclusion policies (39.2%-46%), and internal requirements that exclude secondary content (6.5%-11.6%). In the case of Dimensions, the only classic bibliographic database with the lowest coverage (7.6%), internal selection criteria such as the indexation of full books instead of book chapters (65%) and the exclusion of secondary content (15%) are the main motives of missing publications.
    Source
    Journal of the Association for Information Science and Technology. 75(2023) no.1, S.43-58
  2. Ortega, J.L.: ¬The presence of academic journals on Twitter and its relationship with dissemination (tweets) and research impact (citations) (2017) 0.01 
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    Date
    20. 1.2015 18:30:22
    Source
    Aslib journal of information management. 69(2017) no.6, S.674-687
  3. Ortega, J.L.; Aguillo, I.F.: Visualization of the Nordic academic web : link analysis using social network tools (2008) 0.00 
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    Location
    S
    Source
    Information processing and management. 44(2008) no.4, S.1624-1633
  4. Aguillo, I.F.; Granadino, B.; Ortega, J.L.; Prieto, J.A.: Scientific research activity and communication measured with cybermetrics indicators (2006) 0.00 
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    Source
    Journal of the American Society for Information Science and Technology. 57(2006) no.10, S.1296-1302
  5. Ortega, J.L.; Aguillo, I.F.: Science is all in the eye of the beholder : keyword maps in Google scholar citations (2012) 0.00 
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    Source
    Journal of the American Society for Information Science and Technology. 63(2012) no.12, S.2370-2377
  6. Ortega, J.L.; Aguillo, I.F.: Microsoft academic search and Google scholar citations : comparative analysis of author profiles (2014) 0.00 
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    Source
    Journal of the Association for Information Science and Technology. 65(2014) no.6, S.1149-1156
  7. Ortega, J.L.: Classification and analysis of PubPeer comments : how a web journal club is used (2022) 0.00 
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    Source
    Journal of the Association for Information Science and Technology. 73(2022) no.5, S.655-670

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