Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, hieu lang
hieu sang » hieu lang, hieu quang, nhieu tang
va duong » van duong, va tuong, va dong
va huong » va thuong, va phuong, va tuong
cong van » cong vang, cong san, song van
van phan » van phong, van thanh, luan phan
phan cau » phan dau, phan cac, phan tu

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