Perhaps you should try some spelling variations:
doanh doanh » toan doanh, doanh hoan, doanh thanh
diep quang » dinh quang
hieu quan » hieu qua, lieu quan, thien quan
doanh cua » doanh luan
cua thong » cua thuong, cua khong, cua tong
quan van » luan van, quan va, quan luan
van tai » von tai, van tuan

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((diep quang) or (hieu quan)) - doanh doanh cua thong thong quan van tai~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((diep quang) OR (hieu quan)) - doanh doanh cua thong thong quan van tai.
• Adding a wildcard symbol may retrieve word variants: theo ((diep quang) or (hieu quan)) - doanh doanh cua thong thong quan van tai*.