请教用urlManager进行url重写的匹配问题

现有两条url重写规则

http://search.test.com/s/<keyword:\w+>.htm’ =>‘search/list’,

http://search.test.com/s/<keyword:\w+><length:\w+><pno:\w+><quality:\w+><channelid:\w+>_<orderby:\w+>.htm’ =>‘search/list’,

w+是全部匹配,这样写的话,符合第二行的keyword_length_pno_quality_channelid_orderby.htm的规则就会被第一行的规则认定为keyword,第一行如何改写成keyword匹配但不能含有下划线“_”的规则??