Acad Sinica, Inst High Energy Phys, Beijing 100039, Peoples R China
; Acad Sinica, Inst Theoret Phys, Beijing 100080, Peoples R China
We suggest that in hard scattering processes the nuclear medium can be viewed as a background parton sea where the bound nucleons are "soaked". The quark and gluon distributions in nuclei are investigated under this assumption. The comparisons of this model with the experimental data of the structure function ratio from charged lepton deep inelastic scattering, the gluon momentum distribution ratio from inelastic J/psi production, and the dimuon yield ratio from Drell-Yan dimuon production are present.