Perhaps you should try some spelling variations:
thanh trung » thanh tung
nhung cong » dung cong, thong cong, hang cong
hieu cac » hieu luc, hieu va, dieu can
vien cac » vien bach, vien dai, vien da
hieu van » hieu va, thien van, lieu va
trung va » truong va, trang va, trung ha
cong san » cong tac
san than » sang than, san thanh, ban than
than cap » khan cap, thanh lap, thanh cac

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