API to any Search Engine Callable by PHP

There are search engines that allow you to buy programmer access to their search results. I used to have one. I paid a monthly fee and got the results using a PHP function. The input was my account number, their domain, path and a query where the parameters include the search term. It returned the search results. (This is the natural way to implement this.)

I would like to have that to the biggest search engines I can. If you'll make a list of the possibilities I will choose one or more. It has to be called by PHP under Windows (XAMPP.)