Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
nang co » nang cao, nang doc, nang noi
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
vai cua » dai cua, hai cua, lai cua
nang o » nang ho, nang ro, nang x
qua am » quan am, qua ap, cua am

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang o) OR (nang co)) hoi. hieu qua am thuc ((va danh) OR (va hanh)) vai cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang o) or (nang co)) hoi. hieu qua am thuc ((va danh) OR (va hanh)) vai cua viet~".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang o) or (nang co)) hoi. hieu qua am thuc ((va danh) OR (va hanh)) vai cua viet*.