Perhaps you should try some spelling variations:
chieu sang » chieu xanh, hieu lang, nhieu tang
chieu sach » chinh sach, chiet tach, chieu xanh
canh trinh » canh tranh, hanh trinh, canh tinh
trinh van » trinh han, trinh quan, trinh toan
van phong » van dong, hai phong
cong hoan » cong hoa, dong hoa, cong san
cong dan » cong san, cong tan, huong dan

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

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