$re = '/(\d+)$/m';
$str = 'http://....rech_cod_cat=1&rech_cod_rub=&rech_cod_typ=&rech_cod_sou_typ=&rech_cod_pay=TN&rech_cod_reg=&rech_cod_vil=&rech_cod_loc=&rech_prix_min=&rech_prix_max=&rech_surf_min=&rech_surf_max=&rech_age=&rech_photo=&rech_typ_cli=&rech_order_by=31&rech_page_num=829';
preg_match_all($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