Figure 2. Research status and publication trend of copper(II)-related studies. (A) Analysis of the worldwide distribution of publications showed China, India and USA are the most prolific countries. (B) Analysis of the mean article citations in the most prolific 20 countries showed the USA made the most significant impact in copper(II)-related research. (C) A linear relationship is found between NPs and time (R square = 0.9781, p<0.0001). (D) Copper(II)-related studies distribution in pan-cancer showed breast cancer, lung cancer and prostate cancer are the top 3 research fields. (E) Keywords distribution.