Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, trung cap
cong danh » cuong danh, cong thanh, cong khanh
hoc hieu » hoc thieu, hoc hien, doc hieu
cua dang » cua cong, cua ban
cong dan » cong san, cong tan, huong dan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu lang - thanh trung cua dang ((cong danh) or (cong dan)) van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - thanh trung cua dang ((cong danh) OR (cong dan)) van ban.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - thanh trung cua dang ((cong danh) or (cong dan)) van ban*.