Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu quang » thieu quang, hieu quan, hieu qua
tham nhung » thi nhung
nhung tung » nhung tuong, nhung dung, nhung vung
hieu lang » chieu sang, nhieu tang, hieu van
tung dan » dung dan, huong dan, trung dai
dan toan » van toan, dan than, manh toan
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: ho ((hieu lang) OR (hieu quang)) - ((thanh trung) OR (thanh cong)) tham nhung tung dan toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu lang) OR (hieu quang)) - ((thanh trung) or (thanh cong)) tham nhung tung dan toan cao~".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu lang) OR (hieu quang)) - ((thanh trung) or (thanh cong)) tham nhung tung dan toan cao*.