Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
dam thuc » am thuc, dan thuc, nam thuc
cua viet » ca viet, cua vat, cua dieu
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ky sang » ky nang, ky dang, ky tang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
dam tu » nam tu, cam tu, tam tu

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 mai hoi. hieu ve ((dam thuc) or (dam tu)) 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 mai hoi. hieu ve ((dam thuc) OR (dam tu)) va hanh vi ((cua viet) OR (hoa viet)).
• Adding a wildcard symbol may retrieve word variants: su sach ky sang mai hoi. hieu ve ((dam thuc) or (dam tu)) va hanh vi ((cua viet) or (hoa viet))*.