Perhaps you should try some spelling variations:
cong quang » luong quang, thong quang, duong quang
hieu lang » chieu sang, hieu quang, nhieu tang
hanh mang » nhanh mang, hanh trang, nhanh lang
dung cong » dung trong
toan cao » toan ban, toan tap
ho hieu » ho chieu, hoi hieu, nho hieu
mang va » mang vua, hang va, bang va
va dung » van dung, va duong, vat dung

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 mang va dung cong quang ((toan cao) or (van ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - hanh mang va dung cong quang ((toan cao) OR (van ban)).
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh mang va dung cong quang ((toan cao) or (van ban))*.