Perhaps you should try some spelling variations:
sach moi » sach doi, sach hoi, bach mai
moi nang » hoi nang, voi nang, moi dang
hieu van » thien van, lieu va, hieu ve
hanh dai » hanh tai, hanh dao, vanh dai
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
ma hoi » mai hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach moi nang ((ma hoi) or (xa hoi)). ((hieu van) or (hieu va)) am thuc va hanh dai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach moi nang ((ma hoi) OR (xa hoi)). ((hieu van) OR (hieu va)) am thuc va hanh dai cua viet.
• Adding a wildcard symbol may retrieve word variants: tu sach moi nang ((ma hoi) or (xa hoi)). ((hieu van) or (hieu va)) am thuc va hanh dai cua viet*.