Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
tranh cua » doanh cua, manh cua
dung cong » dung trong
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.

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((chieu sang) OR (hieu lang)) - hanh tranh cua ((dang cong) or (dung cong)) dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu sang) OR (hieu lang)) - hanh tranh cua ((dang cong) OR (dung cong)) dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sang) OR (hieu lang)) - hanh tranh cua ((dang cong) or (dung cong)) dan toan cau".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) OR (hieu lang)) - hanh tranh cua ((dang cong) or (dung cong)) dan toan cau*.