Perhaps you should try some spelling variations:
nang lai » nang tai, mang lai, nang cai
hanh via » hanh vi, hanh va, hanh ve
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
van bac » van ban, van bao, van hac
lai hoi » dai hoi, lai hoa, lai roi
anh va » hanh va
bo va » bao va, do va, co va
so va » so van, so vat, su va

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 ky nang lai hoi. hieu van bac ((bo va) or (so va)) ((hanh via) OR (anh va)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang lai hoi. hieu van bac ((bo va) OR (so va)) ((hanh via) OR (anh va)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang lai hoi. hieu van bac ((bo va) or (so va)) ((hanh via) OR (anh va)) cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang lai hoi. hieu van bac ((bo va) or (so va)) ((hanh via) OR (anh va)) cua tre*.