Perhaps you should try some spelling variations:
thien van » thi van
lam duoc » nam duoc, luat duoc, lam thuoc
va thanh » gia thanh, ban thanh, le thanh
nang hai » hang hai, nang tai, dang hai
hieu van » hieu va, lieu va, hieu ve
hai cua » thai cua, dai cua, hoi cua
va tinh » may tinh
cua tre » cua te, cuu tre, cua triet
hai hoi » dai hoi, hai moi, hai hai
can ky » van ky, dan ky, ban ky
su can » su van, su cao, tu can

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

• Performing a fuzzy search may retrieve terms with similar spellings: su can ky nang hai hoi. ((hieu van) OR (thien van)) lam duoc ((va thanh) or (va tinh)) hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su can ky nang hai hoi. ((hieu van) OR (thien van)) lam duoc ((va thanh) OR (va tinh)) hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su can ky nang hai hoi. ((hieu van) OR (thien van)) lam duoc ((va thanh) or (va tinh)) hai cua tre".
• Adding a wildcard symbol may retrieve word variants: su can ky nang hai hoi. ((hieu van) OR (thien van)) lam duoc ((va thanh) or (va tinh)) hai cua tre*.