Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hieu lang » chieu sang, hieu quang, nhieu tang
dang cong » dung cong
cong chu » cong chuc, cong chua, cong cu
chu dang » chu bang, chu dong, thu dang
cong dan » cong san, cong tan, huong dan
dan van » dang van, doan van, dao van

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((hieu lang) or (chieu sach)) - thanh cong chu dang cong dan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((hieu lang) OR (chieu sach)) - thanh cong chu dang cong dan van ban.
• Adding a wildcard symbol may retrieve word variants: doi ((hieu lang) or (chieu sach)) - thanh cong chu dang cong dan van ban*.