Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu sang, chieu tinh
hanh trong » hanh trang, anh trong, hinh trong
hieu lang » chieu sang, hieu quang, nhieu tang
trong van » trong cac
dong cong » duong cong, dung cong, dang cong
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
toan cau » 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: theo ((chieu xanh) OR (hieu lang)) - hanh trong van dong cong tac toan cau~.
• Adding a wildcard symbol may retrieve word variants: theo ((chieu xanh) or (hieu lang)) - hanh trong van dong cong tac toan cau*.