$str = '<a href="http://adfa.com/adfas.php?dsa=adf&sdfa=dfsdf" target="adf">';
preg_match('#http://[^\'\"\s]+?#isU',$str,$ar);//or preg_match('/http:\/\/[^\'\"\s]+?/isU',$str,$ar);print_r($ar);
preg_match('#http://[^\'\"\s]+?#isU',$str,$ar);//or preg_match('/http:\/\/[^\'\"\s]+?/isU',$str,$ar);print_r($ar);
echo preg_replace('/(.*?)\-([^\_]+?)\_([^\.]+?)\.([^\.]+)/','\\1.php?\\2=\\3',$str);