  Production of Drell-Yan pairs and open and hidden heavy flavor on nuclear
targets is examined within perturbative QCD. The effects of modifications of
nucleon structure functions inside the nuclear medium are considered. Besides,
nuclear dependence of charmonium and bottonium absorption is studied in the
framework of the Glauber-Gribov model. The low energy limit of this approach
recovers the probabilistic formula usually employed for charmonium and
bottonium suppression in nuclear collisions.
