检查which pip 的输出，最有可能的 pip 没有安装.如果它不是来自 venv 的 pip 还要检查 which python.如果不是 venv 的 python，则说明您不在新环境中 - 应该有一些错误.

Check the output of which pip, most likly pip is not installed. If it is not pip from venv also check which python. If it is not venv's python, your are not in the new env - there should be some errors.

如果只缺少 pip 尝试安装:

If only pip is missing try to install with:

curl --silent --show-error --retry 5 https://bootstrap.pypa.io/get-pip.py | python

编辑

Virualenv 仅适用于当前的 shell 会话.要在另一个会话/终端/窗口中使用，您必须再次激活它.它会一直存在，直到您停用它.

Virualenv is only for current shell session. To use in another session/terminal/window you must activate it again. It persists until you deactivate it.