Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van dinh » van minh, va dinh, xuan dinh
su sach » so sach, vu sach
cao hoi » cau hoi, co hoi, cao hoc
van cac » van hac, van cau, van bac
cac luc » cau luc, coc luc, cac nuoc
va hanh » van hanh, va thanh, va danh
so viet » hoc viet
y nang » ky nang, ly nang, v nang
hai so » dai so, tai so, thai son

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang cao hoi. hieu van cac luc ((va hanh) or (((van dinh) or (van dich)))) hai so viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang cao hoi. hieu van cac luc ((va hanh) OR (((van dinh) OR (van dich)))) hai so viet.
• Adding a wildcard symbol may retrieve word variants: su sach y nang cao hoi. hieu van cac luc ((va hanh) or (((van dinh) or (van dich)))) hai so viet*.