Perhaps you should try some spelling variations:
nhung cong » thong cong, hang cong, nhung don
dung cong » dung trong
ho chieu » theo chieu, hoc thieu, doi chieu
hanh ban » thanh ban, hang ban, hanh san
tac toan » tap toan, tam toan, hach toan
toan tap » toan ban
ban cua » ban quan

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((theo tieu) or (ho chieu)) xanh - hanh ban cua ((nhung cong) OR (dung cong)) tac toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((theo tieu) OR (ho chieu)) xanh - hanh ban cua ((nhung cong) OR (dung cong)) tac toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((theo tieu) or (ho chieu)) xanh - hanh ban cua ((nhung cong) OR (dung cong)) tac toan tap".
• Adding a wildcard symbol may retrieve word variants: ((theo tieu) or (ho chieu)) xanh - hanh ban cua ((nhung cong) OR (dung cong)) tac toan tap*.