Perhaps you should try some spelling variations:
duong cong » dung cong, luong cong, duong trong
chieu sang » chieu sach, chieu xanh, hieu lang
hieu sang » hieu lang, hieu quang, nhieu tang
tranh va » tranh van, trang va, trinh va
va duong » van duong, va tuong, va huong
cong van » cong vang, cong san, song van
phan cau » phan dau, phan cac, phan lap

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 (chieu sang)) - canh tranh va duong cong van ((phan cau) OR (phan tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (chieu sang)) - canh tranh va duong cong van ((phan cau) OR (phan tu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) or (chieu sang)) - canh tranh va duong cong van ((phan cau) OR (phan tu))".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (chieu sang)) - canh tranh va duong cong van ((phan cau) OR (phan tu))*.