Perhaps you should try some spelling variations:
trinh hieu » trinh dieu, trinh thiet, trinh nhiet
hieu luat » hieu qua
doanh cua » doanh luan
viet nami » viet nam, vien nam, viet nang
hien huan » hien thuan, hien quan, tien huan
tien duan » tien dua, tien huan, tien quang
danh cua » manh cua, dinh cua, dan cua
nami hoc » dai hoc, bai hoc, nang hoc

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: giao trinh hieu luat ((danh cua) OR (doanh cua)) nguoi viet nami hoc ((hien huan) OR (tien duan))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "giao trinh hieu luat ((danh cua) OR (doanh cua)) nguoi viet nami hoc ((hien huan) or (tien duan))~".
• Adding a wildcard symbol may retrieve word variants: giao trinh hieu luat ((danh cua) OR (doanh cua)) nguoi viet nami hoc ((hien huan) or (tien duan))*.