Perhaps you should try some spelling variations:
quang dung » quang trung, ung dung, cuong dung
canh tinh » hanh tinh, manh tinh, canh tranh
dung cong » dung trong
theo chu » theo chieu, cho chu, chao chu
chu xanh » chu manh, chieu xanh, chua xang
tan toan » tan tran, tap toan, van toan
tap doan » tap quan

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 chu xanh - canh tinh quang dung cong ((tan toan) OR (tap doan)) cau~.
• Adding a wildcard symbol may retrieve word variants: theo chu xanh - canh tinh quang dung cong ((tan toan) or (tap doan)) cau*.