Search multiple keywords (php function)

Hi all!
Is it somehow possible to set WordPress to search multiple keywords? Like red+blue?

I use this code to display specific search results on a page and I would like to be able to set 2 keywords.

<?php 
/*
Template Name: Custom Search Page
*/
$s = 'your search query';
$args = array(
    's' => $s
);
// The Query
$the_query = new WP_Query( $args );
if ( $the_query->have_posts() ) {
    _e("<h2>Search Results for: ".get_query_var('s')."</h2>");
    while ( $the_query->have_posts() ) {
       $the_query->the_post();
             ?>
                <li>
                    <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
                </li>
             <?php
    }
} 

Thank you.
Radan