Perhaps you should try some spelling variations:
hieu ve » hieu van
hieu va » lieu va, hieu qua
cao duc » dao duc, cao suc, giao duc
va hanh » van hanh, va thanh, va danh
va tinh » may tinh
cua tre » cua te, cuu tre, cua triet
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
x hoi » xa hoi, o hoi, x ho

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 sac ky nang x hoi. ((hieu ve) OR (hieu va)) cao duc ((va hanh) OR (va tinh)) dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky nang x hoi. ((hieu ve) OR (hieu va)) cao duc ((va hanh) or (va tinh)) dai cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang x hoi. ((hieu ve) OR (hieu va)) cao duc ((va hanh) or (va tinh)) dai cua tre*.