Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hanh hai » thanh hai, nhanh hai, hang hai
hieu ve » hieu va, hieu van
dai hoi » dai hoc, dai moi
cua tre » cua te, cuu tre, cua triet
dai hai » dai han, dai tai, dai thao
va hanh » van hanh, va thanh, va danh
su hai » su tai
ve cac » va cac, vien cac
hai ky » thai ky, hoi ky, hai ly
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su hai ky nang ((dai hoi) or (dai hai)). hieu ve cac nuoc va hanh hai ((cua tre) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su hai ky nang ((dai hoi) OR (dai hai)). hieu ve cac nuoc va hanh hai ((cua tre) OR (cua tu)).
• Adding a wildcard symbol may retrieve word variants: su hai ky nang ((dai hoi) or (dai hai)). hieu ve cac nuoc va hanh hai ((cua tre) or (cua tu))*.