Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hieu lang » chieu sang, hieu quang, nhieu tang
hanh tran » hanh trang, thanh tran, hanh tram
dung cong » dung trong
tran van » luan van
van dung » van dong, xay dung, tin dung
dan toan » van toan, manh toan, xuan toan
dan than » dan chan, ban than, van than

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: ho ((chieu sach) OR (hieu lang)) - hanh tran van dung cong ((dan toan) OR (dan than)) cau~.
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sach) or (hieu lang)) - hanh tran van dung cong ((dan toan) or (dan than)) cau*.