Perhaps you should try some spelling variations:
chieu xanh » chieu sang, chieu tinh, hieu manh
chieu sach » chinh sach, chiet tach, chieu sang
hang cong » dang cong, hang nong, bang cong
anh tang » anh bang, anh dang, anh nang
cong dan » cong san, cong tan, huong dan
toan cao » toan tap
toan ban » van ban
tang va » trang va, tang van, thang va
va hang » van hang, va nang, va lang

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 xanh) OR (chieu sach)) - anh tang va hang cong dan ((toan cao) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu xanh) OR (chieu sach)) - anh tang va hang cong dan ((toan cao) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu xanh) OR (chieu sach)) - anh tang va hang cong dan ((toan cao) or (toan ban))".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu xanh) OR (chieu sach)) - anh tang va hang cong dan ((toan cao) or (toan ban))*.