why the sex scenes and nudity for Sharon Stone are very few ??? !!! ???

This original cut of this film (the work print, I imagine) was actually great.
I think the studio got scared about the money (as if this was going to succeed financially regardless of content) not coming in from the potential audience, who are not interested in erotic thrillers anymore. Audiences now in America want to see stupid CGI G-rated childrens' films, or dumb gross-out comedies.
Anyway, the studio ended up cutting out the sex scenes (threesome scene is gone, sex in the therapy office is gone, and the first sex scene between Dr Glass and Catherine is heavily edited), as well as Catherine's therapy scenes (on the DVD there are deleted scenes where she talks about her first sexual encounter with her cousin Helena, and a scene where she calls out Dr Glass on being really phony, and another scene where she manipulates Dr Gardosh into potentially taking on Catherine as a patient). Anyway, the film couldve been amazing if left un-cut. Oh well.