First, search engines do not rank “Sites”, they rank individual pages. And while it is possible to have a “page” rank for multiple keywords, the more keywords you try to rank a single page for, the more diluted your efforts will become.
Generally speaking, it is best to focus on no more than 2 or 3 keywords per page. If you want to target a large number of keywords then create more pages.
Take note of how Wikipedia creates individual pages for each targeted keyword, and the optimization is for that single keyword and a few related phrases.