Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
chieu xanh » chieu sach, chieu sang, chieu tinh
hanh trang » thanh trung, canh tranh, hanh trinh
cua dang » cua cong
cong van » cong vang, cong san, song van
van toan » van tuan, van tan, van thanh
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu quang) or (chieu xanh)) - hanh trang ((cua dang) OR (cua ban)) cong van toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu quang) OR (chieu xanh)) - hanh trang ((cua dang) OR (cua ban)) cong van toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu quang) or (chieu xanh)) - hanh trang ((cua dang) OR (cua ban)) cong van toan ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu quang) or (chieu xanh)) - hanh trang ((cua dang) OR (cua ban)) cong van toan ban*.