Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
nhung cong » thong cong, hang cong, nhung don
dung cong » dung trong
ho chieu » theo chieu, hoc thieu, doi chieu
than cau » phan cau, than cap, thanh chau
toan cau » toan cao, toan ban, toan tap
can van » cac van, can ban, tan van
van va » van vat, van van, ban va

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

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