Perhaps you should try some spelling variations:
nhung huong » nhung phuong, nhung tuong, nhung cong
hieu quang » thieu quang, hieu quan, hieu qua
hieu sang » chieu sang, hieu lang, nhieu tang
tranh cua » doanh cua, manh cua
cua nhung » va nhung
dan toan » dan than, manh toan, xuan toan
van toan » van tuan, van tan, van thanh

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: doc ((hieu sang) OR (hieu quang)) - canh tranh cua nhung huong ((dan toan) OR (van toan)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) or (hieu quang)) - canh tranh cua nhung huong ((dan toan) OR (van toan)) cau~".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu quang)) - canh tranh cua nhung huong ((dan toan) OR (van toan)) cau*.