3.1.2. National Contribution Analysis

According to the author address information in the 2637 publications, 104 countries made contributions to MPs research during the study time period. Table 1 lists the top 10 countries by their NSC times of publications in MPs research field, as well as TNP (with ranking), STC (with ranking), NSCR, and the number of publications cited more than 100 and 50 times. Developed countries, including six European countries, two North American countries, and one Oceania country, along with a developing country (China) occupied leading positions in MPs research. England led the NSC index and was second for STC, which indicated that it produced high quality MPs research. The USA also performed well in the areas of research depth and influence, as it ranked first for STC and had 62 publications that were cited more than 100 times, and 107 publications that were cited more than 50 times. China had the most publications (459), but ranked seventh for NSC. Canada, the other five Europe countries, and Australia also performed well. The 10 countries listed in Table 1 contributed 92.8% of all publications, and the high NSCR values (89.38% on average) indicated that

these countries had great external influence not only in numbers of studies but also in the quality of MPs-related publications.


**Table 1.** The top 10 countries for MPs research ranked by NSC; values for other criteria are given as well.

<sup>1</sup> NSC: Non-self-citation; <sup>2</sup> TNP (R): Total number of publications (ranking); <sup>3</sup> STC(R): Sum of times cited (ranking).4 NSCR: Non-self-citation ratio; <sup>5</sup> ≥100: the number of publications cited more than 100 times; <sup>6</sup> ≥50: the number of publications cited more than 50 times.
