Perhaps you should try some spelling variations:
quang quang » quan quang, dang quang, dung quang
quang dung » quang trung, ung dung, cuong dung
hieu sang » chieu sang, hieu quang, nhieu tang
hieu lang » chieu sang, hieu quang, nhieu tang
trong dan » trong dang, trong san, trong tan
dan toan » van toan, dan than, manh toan
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: doc ((hieu sang) or (hieu lang)) - tinh quang quang dung trong dan toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (hieu lang)) - tinh quang quang dung trong dan toan ban.
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu lang)) - tinh quang quang dung trong dan toan ban*.