Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
hanh hang » thanh hang, hang hang, hanh han
cong san » cong tac
toan cau » toan cao, toan tap
toan tai » toan tap, doanh tai, toan cao
toan ban » van ban
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 - hanh hang va nhung cong san ((((toan cau) or (toan tai))) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - hanh hang va nhung cong san ((((toan cau) OR (toan tai))) OR (toan ban)).
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh hang va nhung cong san ((((toan cau) or (toan tai))) or (toan ban))*.