Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
hanh doanh » hang doanh, chinh doanh, doanh doanh
dong phong » duong phong, dong phuong, dong thong
hieu lang » chieu sang, nhieu tang, hieu van
doanh cua » doanh luan
cua dong » chua dong, cua cong, cua dang
bai toan » bai tap
va toan » van toan, tap toan, va thanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoi ((hieu lang) or (hieu quang)) - hanh doanh cua dong phong ((va toan) OR (bai toan)) tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoi ((hieu lang) OR (hieu quang)) - hanh doanh cua dong phong ((va toan) OR (bai toan)) tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoi ((hieu lang) or (hieu quang)) - hanh doanh cua dong phong ((va toan) OR (bai toan)) tap".
• Adding a wildcard symbol may retrieve word variants: hoi ((hieu lang) or (hieu quang)) - hanh doanh cua dong phong ((va toan) OR (bai toan)) tap*.