Perhaps you should try some spelling variations:
nhung huong » nhung phuong, nhung tuong, nhung dung
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » dung cong, thong cong, hang cong
hieu sang » chieu sang, hieu lang, nhieu tang
tranh cua » doanh cua, manh cua
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan tap

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) OR (nhung cong)) dan 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) OR (nhung cong)) dan toan cau~".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu quang)) - canh tranh cua ((nhung huong) OR (nhung cong)) dan toan cau*.