Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu tinh, hieu manh
chieu sang » chieu sach, hieu lang, nhieu tang
canh tinh » hanh tinh, manh tinh, canh tranh
tinh van » trinh van, dinh van, tinh va
van hang » van khang, van hoang, van thang
cong san » cong tac
chan cau » phan cau, can cau, chinh cau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu xanh) OR (chieu sang)) - canh tinh van hang ((huong dan) OR (cong san)) chan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu xanh) OR (chieu sang)) - canh tinh van hang ((huong dan) or (cong san)) chan cau~".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu xanh) OR (chieu sang)) - canh tinh van hang ((huong dan) or (cong san)) chan cau*.