Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
hanh vai » hanh vi, hanh va, hanh tai
cua viet » ca viet, hoa viet, cua vat
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
sang ma » tang ma, nang ma, sang tao
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
vai cua » dai cua, hai cua, lai cua
ve nam » he nam, va nam, le nam

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky ((sang ma) or (mang may)) hoi. hieu ve nam thuc va hanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky ((sang ma) OR (mang may)) hoi. hieu ve nam thuc va hanh vai cua viet.
• Adding a wildcard symbol may retrieve word variants: so sach ky ((sang ma) or (mang may)) hoi. hieu ve nam thuc va hanh vai cua viet*.