Perhaps you should try some spelling variations:
cao hoi » cau hoi, co hoi, cao hoc
hieu va » lieu va, hieu qua
cac toi » cac thoi
ta hanh » ta thanh, va hanh, da hanh
tu hanh » du hanh, lu hanh, thuc hanh
cua tre » cua te, cuu tre, cua triet
vu san » va san, vu ban
tu ban » thu ban, te ban

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: ((vu san) OR (tu ban)) ky nang cao hoi. hieu va cac toi ((ta hanh) OR (tu hanh)) dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu san) or (tu ban)) ky nang cao hoi. hieu va cac toi ((ta hanh) OR (tu hanh)) dai cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((vu san) or (tu ban)) ky nang cao hoi. hieu va cac toi ((ta hanh) OR (tu hanh)) dai cua tre*.