Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu tinh, hieu manh
chieu sang » chieu sach, hieu lang, nhieu tang
hanh tranh » canh tranh, hanh trinh, hanh trang
van dung » van dong, xay dung, tin dung
cong tac » cong ty
tac than » tac thanh, tam than, tac nhan
than cao » toan cao, thai cao, than cap
va dung » va duong, vat dung, va ung

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: hoc ((chieu xanh) OR (chieu sang)) - hanh tranh ((va dung) OR (van dung)) cong tac than cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu xanh) OR (chieu sang)) - hanh tranh ((va dung) or (van dung)) cong tac than cao~".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu xanh) OR (chieu sang)) - hanh tranh ((va dung) or (van dung)) cong tac than cao*.