Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, cam thu
hai chu » hai chau, hoi chu, hai chi
hai cau » hai chau, hai hau, hoi cau
thuc va » thuc vat, thuc dan, thuc day
sach ly » sach y, sach lo, sach ty
su sach » so sach, vu sach
lai hoi » dai hoi, lai hoa, lai roi
ly nang » ky nang, ly hang, ly vang
van cam » van nam, van lam, van cau
va dao » ca dao
ma hoi » mai hoi, xa hoi, ma hoa

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