Hi everyone.. where can i download auto cad 3d models that i can efficiently work in autocad 2010?

hi everyone.. where can i download auto cad 3d models that i can efficiently work in autocad 2010???? am not asking about 3dx max models....i just want 3d models in auto cad 2010 like cars, buildings, apartments, interior designs all such things....so any websites... pls sugest and help me......