Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
nang lai » nang tai, mang lai, nang cai
su sach » so sach
hieu va » lieu va, hieu qua
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
cam luc » cam xuc, cau luc
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
lai hoi » dai hoi, lai hoa, lai roi
vu sach » vu bach, vu khach
luc va » duc va, tuc va, loc va
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (vu sach)) y nang lai hoi. ((hieu ve) OR (hieu va)) cam luc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) y nang lai hoi. ((hieu ve) OR (hieu va)) cam luc va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) y nang lai hoi. ((hieu ve) OR (hieu va)) cam luc va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) y nang lai hoi. ((hieu ve) OR (hieu va)) cam luc va hanh vai cua tre*.