Perhaps you should try some spelling variations:
quang quang » quan quang, dang quang, dung quang
quang trung » truong trung
trung trong » truong trung, thuong trong, dung trong
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
van thanh » ban thanh, van tuan
van toan » van tuan, van tan, manh 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 ((hieu lang) OR (chieu sang)) - tinh quang quang trung trong ((van toan) or (van thanh)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu lang) OR (chieu sang)) - tinh quang quang trung trong ((van toan) OR (van thanh)) ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu lang) OR (chieu sang)) - tinh quang quang trung trong ((van toan) or (van thanh)) ban".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu lang) OR (chieu sang)) - tinh quang quang trung trong ((van toan) or (van thanh)) ban*.