Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
chi vanh » chi anh, chi danh, chi hanh
tranh va » tranh van, trang va, trinh va
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan ban » van ban
chi van » thi van, chu van

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((chi vanh) or (chi van)) - canh tranh va nhung cong tap toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((chi vanh) OR (chi van)) - canh tranh va nhung cong tap toan ban.
• Adding a wildcard symbol may retrieve word variants: doi ((chi vanh) or (chi van)) - canh tranh va nhung cong tap toan ban*.