Perhaps you should try some spelling variations:
trinh quan » tinh quang
hieu lang » chieu sang, hieu quang, nhieu tang
dung cong » dung trong
hai hieu » hai chieu, hoi hieu, phan hieu
cong tan » cong tac, cong san, cong thanh
tan toan » tan tran, tap toan, van toan
toan cau » toan cao, toan ban, toan tap
luat » luan, xuat

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: hai hieu lang - hanh ((((trinh quan) OR (trinh luat))) OR (trinh han)) dung cong tan toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hai hieu lang - hanh ((((trinh quan) OR (trinh luat))) or (trinh han)) dung cong tan toan cau~".
• Adding a wildcard symbol may retrieve word variants: hai hieu lang - hanh ((((trinh quan) OR (trinh luat))) or (trinh han)) dung cong tan toan cau*.