Perhaps you should try some spelling variations:
quang thanh » quan thanh, hoang thanh, muong thanh
chieu sang » chieu sach, hieu lang, nhieu tang
chieu xanh » chieu sach, chieu tinh, hieu manh
cong trong » cong thuong, duong trong, cong trinh
trong ca » trong cac, trong nha
toan ban » van ban
ca toan » cua toan, va toan, bai toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((chieu sang) or (chieu xanh)) - tinh quang thanh cong trong ca toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((chieu sang) OR (chieu xanh)) - tinh quang thanh cong trong ca toan ban.
• Adding a wildcard symbol may retrieve word variants: doc ((chieu sang) or (chieu xanh)) - tinh quang thanh cong trong ca toan ban*.