Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
doi chieu » doc hieu, doi chi, mot chieu
chinh cua » chinh ca, chinh sua, hinh cua
dang cong » dung cong
ho chieu » theo chieu, hoc thieu, mot chieu
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((ho chieu) or (doi chieu)) xanh - hanh chinh cua ((nhung cong) or (dang cong)) tac toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (doi chieu)) xanh - hanh chinh cua ((nhung cong) OR (dang cong)) tac toan cau.
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (doi chieu)) xanh - hanh chinh cua ((nhung cong) or (dang cong)) tac toan cau*.