Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
hieu ve » hieu va, hieu van
cao duc » dao duc, cao suc, giao duc
va hanh » van hanh, va thanh, va danh
tai cua » thai cua, tai cuc, tri cua
tu sai » tu bai, tu san, tu cai
sai ky » sac ky
nang o » nang co, nang ho, nang ro
cua te » cua tu
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sai ky nang o hoi. hieu ve ((pham duc) or (cao duc)) va hanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sai ky nang o hoi. hieu ve ((pham duc) OR (cao duc)) va hanh tai cua te.
• Adding a wildcard symbol may retrieve word variants: tu sai ky nang o hoi. hieu ve ((pham duc) or (cao duc)) va hanh tai cua te*.