Regular Expression Search String Help

[sonyc]

Here is the code to do a Regex search using OR for keywords

$keyword = explode(' ', $_REQUEST['searchInput']);
$regex = "/".implode('|', $keyword)."/i";
if (preg_match($regex, $someStringToSearch)) {
  $result .= "$value.<br>";
} 

How do you write a RegEx or AND all the keywords? That mean all the keywords must be in the $someStringToSearch...

Thanks alot