https://pypi.tuna.tsinghua.edu.cn/simple
https://mirrors.aliyun.com/pypi/simple/
https://pypi.mirrors.ustc.edu.cn/simple/
https://pypi.hustunique.com/
https://pypi.sdutlinux.org/
https://pypi.douban.com/simple/
实例?
pip install numpy -i https://mirrors.aliyun.com/pypi/simple/?
(numpy可以被替换)