BEIJING -- Chinese researchers issued 71,000 scientific papers that were the results of international collaboration in 2015, climbing to the third in the world, according to a report.

The report, jointly issued by the National Center for Science and Technology Evaluation (NCSTE) and Clarivate Analytics, said that since 2006, China has strengthened international cooperation in science and technology.

Expenditure on research and development (R&D) accounted for 1.42 percent of GDP in 2006 and the ratio increased to 2.1 percent in 2016, said the report.

Wang Ruijun, director of the NCSTE, said that during ten years of international cooperation in scientific research, Chinese scientific research workers have played a bigger role in highly cited research papers.

In 2015, the average number of citations of Chinese papers with international partners was 1.5, higher than the global average level.

The NCSTE is a national professional sci-tech evaluation institute, affiliated to the Ministry of Science and Technology.