Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
chieu sach » chinh sach, chiet tach, chieu sang
cong thanh » dong thanh, cong trinh, cong tan
tuong cong » truong cong, trong cong, tong cong
hieu lang » chieu sang, nhieu tang, hieu van
thanh va » thanh van, hanh va, thanh ha
va tuong » va thuong, va thong, xa truong
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan tap » toan ban

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((chieu sach) OR (((hieu lang) OR (hieu quang)))) - cong thanh va tuong cong dan toan tap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi ((chieu sach) or (((hieu lang) OR (hieu quang)))) - cong thanh va tuong cong dan toan tap~".
• Adding a wildcard symbol may retrieve word variants: doi ((chieu sach) or (((hieu lang) OR (hieu quang)))) - cong thanh va tuong cong dan toan tap*.