Perhaps you should try some spelling variations:
quan trong » gian trong
hieu lang » chieu sang, hieu quang, nhieu tang
lanh ban » lanh bang, lang ban, doanh ban
ban quan » van quan
cong tac » cong ty
toan cau » toan cao, toan ban, toan tap
ho hieu » ho chieu, hoi hieu, nho hieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho hieu lang - lanh ban quan trong ((cong san) or (cong tac)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - lanh ban quan trong ((cong san) OR (cong tac)) toan cau.
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - lanh ban quan trong ((cong san) or (cong tac)) toan cau*.