Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
mai khoi » mai khoa, tai khoa, cac khoi
nam thuc » nam thuoc, am thuc, nam thu
hanh mai » hanh ma, hanh mau, hanh may
va triet » va thiet, va trien, ve triet
sach ky » sac ky, sach y, sach ty
sach tu » sach thu, cach tu, sach ty
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
va nam » van nam, ha nam, va nay

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) or (sach tu)) sang mai khoi. hieu va nam thuc va hanh mai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach tu)) sang mai khoi. hieu va nam thuc va hanh mai va triet.
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach tu)) sang mai khoi. hieu va nam thuc va hanh mai va triet*.