function ara($bas, $son, $yazi)
{
@preg_match_all('/' . preg_quote($bas, '/') .
'(.*?)' . preg_quote($son, '/') . '/s', $yazi, $m);
return @$m[1];
}

Örnek kullanım

$sonuc = ara("monday","bus",$yazi);

var_dump($sonuc)