Perhaps you should try some spelling variations:
nhung cong » dung cong, hang cong, nhung don
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
tinh cua » trinh cua, sinh cua, tinh chat
quan dau » qua dau, quan dac, quan doan
quan cau » quang cao, toan cau, quan ha
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 tinh cua ((nhung cong) or (thong cong)) trinh ((quan dau) OR (quan cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - hanh tinh cua ((nhung cong) OR (thong cong)) trinh ((quan dau) OR (quan cau)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - hanh tinh cua ((nhung cong) or (thong cong)) trinh ((quan dau) OR (quan cau))".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh tinh cua ((nhung cong) or (thong cong)) trinh ((quan dau) OR (quan cau))*.