Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
sach ky » sac ky, sach y, sach ty
so sach » so sanh, bo sach, co sach
sang ma » tang ma, nang ma, sang tao
ve nam » he nam, le nam, te nam
va nam » van nam, ha nam, va nay
vi cua » vai cua, di cua

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) OR (va nam)) thuc va hanh vi 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) OR (va nam)) thuc va hanh vi cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky ((sang ma) or (mang may)) hoi. hieu ((ve nam) OR (va nam)) thuc va hanh vi cua viet".
• Adding a wildcard symbol may retrieve word variants: so sach ky ((sang ma) or (mang may)) hoi. hieu ((ve nam) OR (va nam)) thuc va hanh vi cua viet*.