Disallow: /productlist.php?*
Disallow: /productlist.php?cat=*&*
Disallow: /productlist.php?cat=*&page=*&*
Disallow: /productlist.php?cat=*&*&page=*
Disallow: /productlist.php?cat=*&*&page=*&*

Allow: /productlist.php?cat=*
Allow: /productlist.php?cat=*&page=*