Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
hieu sang » chieu sang, hieu lang, nhieu tang
tranh cua » doanh cua, manh cua
hang cong » dang cong, hang nong, thanh cong
bang cong » dang cong, bang song, dung cong
van toan » van tuan, van tan, van thanh
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: doc ((hieu sang) or (hieu quang)) - canh tranh cua ((hang cong) OR (bang cong)) van toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (hieu quang)) - canh tranh cua ((hang cong) OR (bang cong)) van toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) or (hieu quang)) - canh tranh cua ((hang cong) OR (bang cong)) van toan cao".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu quang)) - canh tranh cua ((hang cong) OR (bang cong)) van toan cao*.