Perhaps you should try some spelling variations:
sach doi » sach hoi, sach moi, sach dao
doi nang » dai nang, hoi nang, voi nang
cam thuc » am thuc, nam thuc, cam thu
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
hai hau » hai chau, dai hau, hai hai
ma hoi » mai hoi, xa hoi, ma hoa
va cam » va cham, va cac, va cao

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 doi nang ma hoi. hieu va cam thuc va danh ((hai hau) or (lai chau)) treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach doi nang ma hoi. hieu va cam thuc va danh ((hai hau) OR (lai chau)) treo.
• Adding a wildcard symbol may retrieve word variants: su sach doi nang ma hoi. hieu va cam thuc va danh ((hai hau) or (lai chau)) treo*.