newbie question, real positive solutions of an equation

I'm using Maxima to solve some equations, which Maxima does very well.
Maxima shows me _all_ the roots: positive, negative, zero and 
complex. 
I suppose there must be a method to show only the roots which are 
real and positive. Or maybe it is possible to make Maxima look only for 
the positive ones thus not wasting time looking for complex and negative 
roots?
Can anyone here tell me how to accomplish this?

hugo