$re = '/(((\w+\^\(.*?\)|([\w\^]+))|(\(?\(([^\(\)]+)\)\)?))(((\/)(?!\-))|((\*)(?!\-))|(\/\-)|(\*\-))?\(([^\(\)]+)\))|(\(([^\(\)]+)\)((((\/)(?!\-))|((\*)(?!\-))|(\/\-)|(\*\-))?((\w+\^\(.*?\)|([\w\^]+))|(\(?\(([^\(\)]+)\)\)?))))/x';
$str = '(sdf^sdf*(sdf*(23^3s)))*sdf
(232^23)dfdf+dfd(sfsf)
dfd(sfsf^sdf+323)/-13+sfdfsdf
(dfd^23sdf)-(234^dfd)
(dfd^23sdf)-(234^dfd)*(x-3)';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php