I personally use a great deal the function:

get_search_query() 

To obtain the value came back from searchs and also to have the ability to modify and employ the string.

I have to know a function to obtain <?php the_content(); ?> like a string or how you can turn what that funtion returns right into a string.

This content is simply a simple word with paragraph tags but by using their function I additionally obtain the tags, I wish to get only the text in order to combine it with a web link.

I believe you are searching for get_the_content(), that is well recorded: http://codex.wordpress.org/Function_Reference/the_content

Have no idea Wordpress, however the implied naming convention indicate get_the_content(). Additional searching discloses an alternative get_the_content_with_formatting

An alternate could be however to wrap the_content() into ob_start() and ob_get_contents()+ob_end(). The second returns any print output made for now.

You need to use get_the_content() to be able to make have it right into a string, which you'll format.