Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
dao duc » giao duc, tao duoc
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
nang o » nang co, nang ho, nang ro
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 sac ky nang o hoi. hieu van dao duc ((va hanh) or (may tinh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang o hoi. hieu van dao duc ((va hanh) OR (may tinh)) dai cua tre*.