Perhaps you should try some spelling variations:
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu van
hieu va » lieu va, hieu qua
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
cua tre » cua te, cuu tre, cua triet
va sac » va cac, va suc, va san
sac ky » cac ky, sai ky
vi cua » vai cua, di cua
nuoc » quoc, duoc, ngoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: va sac ky nang cao hoi. ((hieu ve) or (hieu va)) dat nuoc va danh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: va sac ky nang cao hoi. ((hieu ve) OR (hieu va)) dat nuoc va danh vi cua tre*.