Searching multiple words in several documents

Hi,

I need to do the same type of searching that this web describe:

http://blogs.adobe.com/acrolaw/2010/04/searching-and-marking-multiple- words-in-a-pdf/

This is possible to do it with Adobe Reader XI? I need to search for example: "USA" and "United States", but if I try to do it AR find string as "United Kingdom". I need it find "United States", but not "United Kingdom". I can first find "USA" and later "United States", but I have to search 8 diferents words and theirs inicials and it would be a waste of time.

Thanks very much.