Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu quan » lieu quan, thien quan, lien quan
tranh cua » doanh cua
manh cua » doanh cua, ban cua
cong san » cong tac
san tan » van tan, san van, san tay
tan cau » toan cau, van cau, tan ca

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 quan) or (hieu qua)) - canh ((tranh cua) OR (manh cua)) nhung cong san tan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu quan) OR (hieu qua)) - canh ((tranh cua) OR (manh cua)) nhung cong san tan cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu quan) or (hieu qua)) - canh ((tranh cua) OR (manh cua)) nhung cong san tan cau*".