Perhaps you should try some spelling variations:
thanh trung » thanh tung
nhung cong » thong cong, hang cong, nhung don
hieu quan » hieu qua, lieu quan, thien quan
dung cong » dung trong
trung va » truong va, trang va, trung ha
tuan tai » toan tai, quan tai, tan tai
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 quan - thanh trung va ((nhung cong) OR (dung cong)) van ((tuyen tap) or (tuan tai))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu quan - thanh trung va ((nhung cong) OR (dung cong)) van ((tuyen tap) OR (tuan tai)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu quan - thanh trung va ((nhung cong) OR (dung cong)) van ((tuyen tap) or (tuan tai))".
• Adding a wildcard symbol may retrieve word variants: ho hieu quan - thanh trung va ((nhung cong) OR (dung cong)) van ((tuyen tap) or (tuan tai))*.