Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, nhung don
dang thanh » dong thanh, dang hanh, hoang thanh
hieu tinh » chieu tinh, lieu tinh, hieu binh
kieu tinh » lieu tinh, trieu tinh, diep tinh
tranh cua » doanh cua, manh cua
hang cong » dang cong, hang nong, bang cong

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((hieu tinh) OR (kieu tinh)) - canh tranh cua ((nhung cong) or (hang cong)) dang thanh san~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu tinh) OR (kieu tinh)) - canh tranh cua ((nhung cong) OR (hang cong)) dang thanh san.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu tinh) OR (kieu tinh)) - canh tranh cua ((nhung cong) or (hang cong)) dang thanh san".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu tinh) OR (kieu tinh)) - canh tranh cua ((nhung cong) or (hang cong)) dang thanh san*.