Perhaps you should try some spelling variations:
thien van » thi van
doc sach » hoc sach, toc sach, nuoc sach
cham duc » pham duc, pham duy, phan duc
hanh dai » hanh tai, hanh dao, vanh dai
sach ty » sach y, sach tu, sach thu
xang xa » lang xa, mang xa, ang xa
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ty xang xa hoi. ((hieu ve) or (thien van)) ((cham duc) or (cham soc)) va hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty xang xa hoi. ((hieu ve) OR (thien van)) ((cham duc) OR (cham soc)) va hanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: doc sach ty xang xa hoi. ((hieu ve) or (thien van)) ((cham duc) or (cham soc)) va hanh dai cua tre*.