Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, hieu ve
te sach » toc sach
sach ky » sac ky, sach y, sach ty
lai hoi » dai hoi, lai roi, mai hoi
lai hoa » dai hoa, loai hoc
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cuu tre, cua triet
va can » va chan, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang ((lai hoi) OR (lai hoa)). ((hieu van) or (lieu va)) cau truc va can dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((lai hoi) OR (lai hoa)). ((hieu van) OR (lieu va)) cau truc va can dai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ((lai hoi) OR (lai hoa)). ((hieu van) or (lieu va)) cau truc va can dai cua tre*".