Perhaps you should try some spelling variations:
cua triet » su triet, va triet
thuc day » thuc dan, thuc vat
day hanh » day nhanh, day thanh, dao hanh
hanh hai » thanh hai, nhanh hai, hang hai
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang co » nang cao, nang doc, nang noi
hieu va » lieu va
co hoi » co hoc, co loi

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 ky nang co hoi. ((hieu va) OR (hieu qua)) am thuc day hanh hai ((cua triet) OR (cua viet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang co hoi. ((hieu va) OR (hieu qua)) am thuc day hanh hai ((cua triet) or (cua viet))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang co hoi. ((hieu va) OR (hieu qua)) am thuc day hanh hai ((cua triet) or (cua viet))*.