帮忙看看什么问题安装laravel

Your requirements could not be resolved to an installable set of packages.

Problem 1
- The requested package laravel/framework could not be found in any version, there may be a typo in the package name.
Problem 2
- The requested package laravel/installer could not be found in any version, there may be a typo in the package name.

Potential causes:
- A typo in the package name
- The package is not available in a stable-enough version according to your minimum-stability setting
see <https://groups.google.com/d/to ... ussion> for more details.

Read <http://getcomposer.org/doc/art ... ing.md> for further common problems.

Installation failed, reverting ./composer.json to its original content.