Knowing which countries contribute the most to pushing the boundaries of knowledge in science and technology has social and political importance. However, common citation metrics do not adequately measure this contribution. This measure requires more stringent metrics appropriate for the highly influential breakthrough papers that push the boundaries of knowledge, which are very highly cited but very rare. Here I used the recently described Rk index, specifically designed to address this issue. I applied this index to 25 countries and the EU across 10 key research topics, five technological and five biomedical, studying domestic and international collaborative papers independently. In technological topics, the Rk indices of domestic papers show that overall, the USA, China, and the EU are leaders; other countries are clearly behind. The USA is notably ahead of China, and the EU is far behind China. The same approach to biomedical topics shows an overwhelming dominance of the USA and that the EU is ahead of China. The analysis of internationally collaborative papers further demonstrates the US dominance. These results conflict with current country rankings based on less stringent indicators.

翻译：了解哪些国家对推动科学与技术知识前沿贡献最大，具有重要的社会和政治意义。然而，传统的引文指标并不能充分衡量这种贡献。这一衡量需要采用更严格的指标，适用于那些推动知识前沿、被高度引用但数量极少的突破性论文。此处我使用了近期提出的Rk指数，该指数专门针对这一问题设计。我将该指数应用于25个国家和欧盟在10个关键研究主题（包括五个技术主题和五个生物医学主题）中的表现，独立分析了国内论文和国际合作论文。在技术主题中，国内论文的Rk指数显示，总体而言，美国、中国和欧盟处于领先地位，其他国家明显落后。美国显著领先于中国，而欧盟远远落后于中国。对生物医学主题采用相同方法分析，则显示美国占据压倒性主导地位，欧盟领先于中国。对国际合作论文的分析进一步证实了美国的主导地位。这些结果与当前基于不太严格指标的国家排名存在冲突。