Perhaps you should try some spelling variations:
vien thanh » viet thanh, tien thanh, dien thanh
nhung cong » dung cong, thong cong, hang cong
hiem ngan » kim ngan, viem gan
tran van » luan van
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than cap » khan cap, thanh lap, thanh cac
tra van » ta van, trang van, tranh van

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((vien thanh) OR (hiem ngan)) - thanh ((tra van) OR (tran van)) nhung cong dan than cap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((vien thanh) or (hiem ngan)) - thanh ((tra van) OR (tran van)) nhung cong dan than cap~".
• Adding a wildcard symbol may retrieve word variants: hoc ((vien thanh) or (hiem ngan)) - thanh ((tra van) OR (tran van)) nhung cong dan than cap*.