Perhaps you should try some spelling variations:
nhung cong » thong cong, hang cong, nhung don
hieu lang » chieu sang, hieu quang, nhieu tang
manh tung » manh hung, thanh tung
dung cong » dung trong
tung cua » trung cua, tuong cua, dung cua
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((hieu lang) or (chinh sach)) - manh tung cua ((nhung cong) or (dung cong)) dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((hieu lang) OR (chinh sach)) - manh tung cua ((nhung cong) OR (dung cong)) dan toan cao.
• Adding a wildcard symbol may retrieve word variants: doi ((hieu lang) or (chinh sach)) - manh tung cua ((nhung cong) or (dung cong)) dan toan cao*.