Those not included in the ranking above are South Korea, China, Brazil and Russia, ranked 21st through 24th, respectively, in citations per paper. South Korea’s 3,395 papers attracted 37,291 citations, earning it an impact score of 10.98. China claimed 55,014 citations for its 6,081 papers, for an impact of 9.05. Brazil had an impact of 7.34 based on ,259 citations for r3,712 papers. Russia published 6,224 papers that collected 40,470 citations, for an impact score of 6.50. By output, these four, if included, would have ranked 12th, 13th, 17th and 19th (Russia, China, Brazil and South Korea, in order). By citations, the four, if included, would have ranked 19th, 20th, 21st and 23rd (China, Russia, South Korea, and Brazil, in order). In this field, Russia and China are world-class producers, but they have yet to become world-class in citation impact.
The data above were extracted from Thomson Scientific’s Essential Science Indicators database. This database, currently covering the period January 1997 to December 2007, surveys only journal articles (original research reports and review articles) indexed by Thomson Scientific. Articles are assigned to a category based on the journals in which they were published and Thomson Scientific’s journal-to-category field-definition scheme. Both articles tabulated and citation counts to those articles are for the period indicated. Here our ranking in molecular biology and genetics is by citations per paper among nations that collected 25,000 or more citations to reveal weighted impact. For articles with multiple authors from different nations, each nation receives full citation credit. Essential Science Indicators lists nations ranked in the top 50 per cent for a field over a given period, based on total citations. In molecular biology and genetics, 88 nations are listed, meaning 176 were surveyed. Twenty-four nations earned at least 25,000 citations. For more on Thomson Scientific’s Essential Science Indicators, see http://scientific.thomson.com/products/esi.