Perhaps you should try some spelling variations:
nhung cong » thong cong, hang cong, nhung don
hanh huong » thanh huong, anh huong, manh huong
hieu lang » chieu sang, hieu quang, nhieu tang
huong cua » dung cua
dung cong » dung trong
van toan » van tuan, van tan, van thanh
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((chinh sach) or (hieu lang)) - hanh huong cua ((nhung cong) OR (dung cong)) van toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chinh sach) OR (hieu lang)) - hanh huong cua ((nhung cong) OR (dung cong)) van toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chinh sach) or (hieu lang)) - hanh huong cua ((nhung cong) OR (dung cong)) van toan tap".
• Adding a wildcard symbol may retrieve word variants: ho ((chinh sach) or (hieu lang)) - hanh huong cua ((nhung cong) OR (dung cong)) van toan tap*.