Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
thuc dan » thuc hanh, hoc dan, thuc vat
dan hanh » dang hanh, dan khanh, dan thanh
co sach » bo sach, cuon sach, hoc sach
sach ty » sach y, sach tu, sach thu
ty hang » ly hang, ty xang, thi hang
hieu le » hieu ve, hieu he, hieu ly
ma hoi » mai hoi, ma hoa, me hoi
le nam » ly nam, he nam, le na

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 ty hang ((ma hoi) or (xa hoi)). hieu le nam thuc dan hanh vi ((hoa viet) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ty hang ((ma hoi) OR (xa hoi)). hieu le nam thuc dan hanh vi ((hoa viet) OR (cua vat)).
• Adding a wildcard symbol may retrieve word variants: co sach ty hang ((ma hoi) or (xa hoi)). hieu le nam thuc dan hanh vi ((hoa viet) or (cua vat))*.