Perhaps you should try some spelling variations:
va thanh » gia thanh, ban thanh, va tinh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
cac luc » cau luc, coc luc, cac nuoc
va hanh » van hanh, va danh, ban hanh
va dinh » van dinh, va kinh, va tinh
so viet » hoc viet
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 ky nang cao hoi. hieu va cac luc ((((va hanh) or (va thanh))) or (va dinh)) hai so viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang cao hoi. hieu va cac luc ((((va hanh) OR (va thanh))) OR (va dinh)) hai so viet.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang cao hoi. hieu va cac luc ((((va hanh) or (va thanh))) or (va dinh)) hai so viet*.