adsense site search for a section of site?

[newbies]

It seems that google only allow us to input root domain (no slash in the domain box is allowed) for site search. Can we set up a section search such as www.myname.com/forum?
(I guess forum.myname.com should be ok, but I don't have the subdomain set up)

Thanks.

Newbies

[NoLimits]

If you forum is located at www.yoursite.com/forum?...

do site://www.yoursite.com forum

it will find "forum" in the url

[newbies]

the problem is google does not allow us to modify the code and it is not convenient to ask users to input "forum" when they do a search.