官网 https://www.r-project.org/
镜像 https://cran.r-project.org/mirrors.html
China
https://mirrors.tuna.tsinghua.edu.cn/CRAN/
TUNA Team, Tsinghua University
http://mirrors.tuna.tsinghua.edu.cn/CRAN/
https://mirrors.ustc.edu.cn/CRAN/
University of Science and Technology of China
http://mirrors.ustc.edu.cn/CRAN/
http://mirror.lzu.edu.cn/CRAN/
Lanzhou University Open Source Society
http://mirrors.xmu.edu.cn/CRAN/
Xiamen University