Perhaps you should try some spelling variations:
quang quan » quang tuan, quang uan, quan quan
chieu xanh » chieu sach, chieu sang, chieu tinh
cong trong » cong thuong, duong trong, cong trinh
hieu lang » chieu sang, hieu quang, nhieu tang
quan cong » qua cong, luan cong, quan dong
trong dan » trong dang, trong san, trong tan
dan than » dan chan, ban than, van than
than ban » thanh ban, toan ban, than man

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

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