Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
thanh tung » thanh cong
hieu lang » chieu sang, nhieu tang, hieu van
trong san » trong cac, cong san, dong san
tan dung » tran dung, van dung, dan dung
san toan » van toan, dan toan, manh toan
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((hieu lang) OR (hieu quang)) - thanh tung ((tan dung) or (tin dung)) trong san toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((hieu lang) OR (hieu quang)) - thanh tung ((tan dung) OR (tin dung)) trong san toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu lang) OR (hieu quang)) - thanh tung ((tan dung) or (tin dung)) trong san toan cau".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu lang) OR (hieu quang)) - thanh tung ((tan dung) or (tin dung)) trong san toan cau*.