Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, hieu lang
nhung cong » dung cong, thong cong, hang cong
hieu manh » chieu xanh, hieu nganh, dieu hanh
ban quan » van quan
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan ban » van ban

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 manh) or (chieu sang)) - hanh ((ban cua) OR (ban quan)) nhung cong san toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu manh) OR (chieu sang)) - hanh ((ban cua) OR (ban quan)) nhung cong san toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu manh) or (chieu sang)) - hanh ((ban cua) OR (ban quan)) nhung cong san toan ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) or (chieu sang)) - hanh ((ban cua) OR (ban quan)) nhung cong san toan ban*.