Perhaps you should try some spelling variations:
doanh khong » doanh thuong, doanh khoa, doanh chung
nghien cua » nghien cuu, nghiep cua, nghiep vua
hoa doanh » toan doanh, hoa dan
cach hoc » cach thuc, cach thoi, dich hoc
cong hoa » dong hoa, dong hoc, hang hoa
nhan van » nhan dan, nhan va, phan van
tu cach » tu cac
va nhan » van nhan, ca nhan, va phan

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cach hoc tap, nghien cua cong hoa doanh khong ((hoc xa) OR (hoc ma)) hoi va nhan van~".
• Adding a wildcard symbol may retrieve word variants: tu cach hoc tap, nghien cua cong hoa doanh khong ((hoc xa) OR (hoc ma)) hoi va nhan van*.