Perhaps you should try some spelling variations:
sang tao » hang tai
hanh dai » hanh tai, hanh dao, vanh dai
co sach » bo sach, cuon sach, hoc sach
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
su viet » so viet
va cau » van cau, va cac, va dau
dai su » dai sua, dai so, dan su

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach y ((nang ma) or (sang tao)) hoi. hieu va cau truc va hanh dai su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach y ((nang ma) OR (sang tao)) hoi. hieu va cau truc va hanh dai su viet.
• Adding a wildcard symbol may retrieve word variants: co sach y ((nang ma) or (sang tao)) hoi. hieu va cau truc va hanh dai su viet*.