Perhaps you should try some spelling variations:
chieu sach » chiet tach, chieu sang, chieu xanh
van khang » van khanh, van thanh, van quang
ban hang » ngan hang
hang van » hoang van, hang va, dang van
cong san » cong tac
nong dan » cong dan, nong san, nguong dan
ban can » ban dan, ban hanh, ban quan

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((chieu sach) OR (chinh sach)) - ban hang van khang ((cong san) or (nong dan)) ban can~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((chieu sach) OR (chinh sach)) - ban hang van khang ((cong san) OR (nong dan)) ban can.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi ((chieu sach) OR (chinh sach)) - ban hang van khang ((cong san) or (nong dan)) ban can".
• Adding a wildcard symbol may retrieve word variants: doi ((chieu sach) OR (chinh sach)) - ban hang van khang ((cong san) or (nong dan)) ban can*.