Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, nhieu tang
cong khanh » cong thanh, cong khan, cong nhan
hieu lang » hieu quang, nhieu tang, hieu van
tranh cua » doanh cua, manh cua
cong hach » cong sach, cong thanh, trong hach
cua dung » cua dang, cua dong, qua dung
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 (chieu sang)) - canh tranh cua dung ((cong hach) or (cong khanh)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((hieu lang) OR (chieu sang)) - canh tranh cua dung ((cong hach) OR (cong khanh)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu lang) OR (chieu sang)) - canh tranh cua dung ((cong hach) or (cong khanh)) toan cau".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu lang) OR (chieu sang)) - canh tranh cua dung ((cong hach) or (cong khanh)) toan cau*.