Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, hieu lang
hieu sang » hieu lang, hieu quang, nhieu tang
dong danh » dong doanh, dong anh, dung danh
anh dung » anh dong, anh huong, sach dung
dung cua » dung luan, dung cho
dong dan » duong dan, dong san, cong dan
toan cao » toan ban, toan tap

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (chieu sang)) - anh dung cua cong ((dong dan) OR (dong danh)) toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) OR (chieu sang)) - anh dung cua cong ((dong dan) or (dong danh)) toan cao~".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) OR (chieu sang)) - anh dung cua cong ((dong dan) or (dong danh)) toan cao*.