Perhaps you should try some spelling variations:
cua viet » ca viet, cua vat, cua dieu
nam thuc » nam thuoc, am thuc, nam thu
mai khoi » mai khoa, tai khoa, cac khoi
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
sach ky » sac ky, sach y, sach ty
hieu le » hieu ve, hieu he, hieu ly
ky sang » ky nang, ky dang, ky tang
le nam » ly nam, he nam, le na
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 ky sang ((ma hoi) or (mai khoi)). hieu le nam thuc va hanh vi ((cua viet) or (hoa viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky sang ((ma hoi) OR (mai khoi)). hieu le nam thuc va hanh vi ((cua viet) OR (hoa viet)).
• Adding a wildcard symbol may retrieve word variants: su sach ky sang ((ma hoi) or (mai khoi)). hieu le nam thuc va hanh vi ((cua viet) or (hoa viet))*.