Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh duc » thach duc, than duc, thinh duc
hieu van » hieu va, thien van, lieu va
hanh dai » hanh tai, hanh dao, vanh dai
sach ky » sach y, sach ty, sach kem
cao hoc » co hoc, cho hoc, chat hoc
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky

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) OR (sac ky)) nang ((cao hoc) or (cau hoi)). hieu van thanh duc va hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sac ky)) nang ((cao hoc) OR (cau hoi)). hieu van thanh duc va hanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) OR (sac ky)) nang ((cao hoc) or (cau hoi)). hieu van thanh duc va hanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) OR (sac ky)) nang ((cao hoc) or (cau hoi)). hieu van thanh duc va hanh dai cua tre*.