Can Yahoo restrict dynamic URLs?

URLs restricted using robots.txt

[Blade3]

Hi,

I had included dynamic URLs in robots.txt as

User-agent: *
Disallow: /file.jsp?pno=

to restrict file.jsp?pno=1, file.jsp?pno=2 and so on.

But Yahoo is still showing these dynamic pages which are restricted from indexing.

Through some light, please.