Perhaps you should try some spelling variations:
hanh hai » thanh hai, nhanh hai, hang hai
su thai » su thi, su tai, su hai
thai ky » thoi ky, than ky, thai ly
dai hoi » dai hoc, dai moi
dai hai » dai han, dai tai, dai thao
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
cua tre » cuu tre, cua triet, dua tren
ve hoc » te hoc, va hoc, vi hoc
cua te » cua tu
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: su thai ky nang ((dai hoi) or (dai hai)). hieu ve hoc nuoc va hanh hai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su thai ky nang ((dai hoi) OR (dai hai)). hieu ve hoc nuoc va hanh hai ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su thai ky nang ((dai hoi) or (dai hai)). hieu ve hoc nuoc va hanh hai ((cua tre) or (cua te))*.