Perhaps you should try some spelling variations:
hieu sach » chieu sach, hieu cach, dien sach
thanh van » thanh san, thanh toan, thanh phan
dung cong » dung trong
thanh ban » thanh san, thanh bac, thanh tan
thanh bai » thanh hai, thanh tai, thanh oai
doc hieu » toc thieu, hoc thieu, hoc hien
tran van » luan van
cong dan » cong san, cong tan, huong dan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sach - hanh ((tran van) OR (thanh van)) dung cong dan ((thanh ban) OR (thanh bai))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu sach - hanh ((tran van) or (thanh van)) dung cong dan ((thanh ban) OR (thanh bai))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu sach - hanh ((tran van) or (thanh van)) dung cong dan ((thanh ban) OR (thanh bai))*.