title: International collaboration of Turkey in liver transplantation research: a bibliometric analysis.
abstract: OBJECTIVE
  Scientific publications are valuable markers of scientific activity for countries. We performed a bibliometric study to evaluate the number of publications written by Turkish authors. The aim of this study is to evaluate Turkey's contribution in terms of number of publications included in Science Citation Index Expanded (SCI-E) in the scientific field of liver transplantation compared with other countries. To our knowledge, this is the first bibliometric study in liver transplantation research of Turkey.
  
  
  METHODS
  ISI Web of Knowledge-Science was used for the analysis. All scientific works published included in SCI-E in English from 1980 to August 10, 2011, were analyzed. A retrospective search was performed using key words "liver transplantation," "hepatic transplantation," "liver transplant," and "hepatic transplant." We further analyzed these results by the "analyze" function of the software in terms of number of papers for each country, type of documentation, number of publications per year, journal, institute, and author. The number of citations to published works was calculated by using the citation function of the same software. We also used the same function of the software to analyze publications from Turkey in the last three decades between 1980 and 1989, 1990 and 1999, and 2000 and 2009 for statistical evaluation. Collected data from the comparison periods were statistically analyzed using the chi-square test.
  
  
  RESULTS
  In all, 48,418 publications related to liver transplantation were included in SCI-E in English between 1980 and August 2011. Overall, 675 of those publications were from Turkey (2.05%). There was no publication from Turkey between 1980 and 1989; 37 between 1990 and 1999; and 511 between 2000 and 2009. The rank of Turkey among other countries according to the number of publications was 25th between 1990 and 1999 and improved to 14th between 2000 and 2009. The number of scientific publications in the field of liver transplantation from Turkey among other countries increased during the last three decades.
  
  
  CONCLUSIONS
  Turkey showed a significant positive trend in publications in the scientific field of liver transplantation in the last 30 years, and the rank of Turkey among other countries improved in recent decades. Currently, Turkey is one of the top 17 countries in terms of number of scientific publications listed in SCI-E. This can be considered as another indicator for Turkey's progress in the field of liver transplantation.
authors.affiliation: Near East University Faculty of Medicine, Department of General Surgery, Lefkosa, Turkey. drkoraybas@yahoo.com
authors.forename: K
authors.initials: K
authors.lastname: Bas
authors.forename: M
authors.initials: M
authors.lastname: Dayangac
authors.forename: O
authors.initials: O
authors.lastname: Yaprak
authors.forename: Y
authors.initials: Y
authors.lastname: Yuzer
authors.forename: Y
authors.initials: Y
authors.lastname: Tokat
mesh_terms: D000818:Animals; D015706:Bibliometrics; D035843:Biomedical Research / Q000639:trends*; D003299:Cooperative Behavior; D006801:Humans; D007391:International Cooperation; D016031:Liver Transplantation / Q000639:trends*; D012189:Retrospective Studies; D013997:Time Factors; D014421:Turkey