Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
hac dac » cac dac, ha dac, nhac dan
van hac » van hoc, van ha, van hai
tu sach » thu sach, te sach, tu cach
cao hoc » co hoc, chat hoc
su sach » so sach, vu sach
cho hoc » co hoc, khoa hoc
y nang » ky nang, ly nang, v nang
dac va » duc va, day va, dat va
vi cua » vai cua, di cua

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: ((tu sach) OR (su sach)) y nang ((cao hoc) OR (cho hoc)). hieu van hac dac va hanh vi cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) y nang ((cao hoc) or (cho hoc)). hieu van hac dac va hanh vi cua viet~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) y nang ((cao hoc) or (cho hoc)). hieu van hac dac va hanh vi cua viet*.