Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
thai cua » than cua, tai cuc, tri cua
khoa hoi » khoan hoi, khoa hoc, khoa doi
vat nang » van nang, va nang, vat mang
hai cua » dai cua, hoi cua, lai cua
hieu he » hieu ve, hiem he, hieu le
hoa hoi » hoa hoc, hoa doi, hoc hoi
ky lang » ky nang, ky dang, ky tang
he nam » ha nam, nghe nam
sac ky » cac ky, sai ky
te sac » te sach, te cac, te san

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky lang ((hoa hoi) or (khoa hoi)). hieu he nam thuc vat nang ((hai cua) or (thai cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky lang ((hoa hoi) OR (khoa hoi)). hieu he nam thuc vat nang ((hai cua) OR (thai cua)) viet.
• Adding a wildcard symbol may retrieve word variants: te sac ky lang ((hoa hoi) or (khoa hoi)). hieu he nam thuc vat nang ((hai cua) or (thai cua)) viet*.