$re = '/(?<=\?first=)[^&]+/m';
$str = 'http://www.example.com.tr/?first=DSPN47ZTE1BGMR&second=NECEFT8RYD
http://www.example.com.tr/?first=RTR22414242144&second=YUUSADASFF
http://www.example.com.tr/?first=KOSDFASEWQESAS&second=VERERQWWFA
http://www.example.com.tr/?first=POLUJYUSD41234&second=13F241DASD
http://www.example.com.tr/?first=54SADFD14242RD&second=TYY42412DD';
preg_match_all($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