Perhaps you should try some spelling variations:
doanh thong » doanh thuong, doanh tong, doanh trong
nghien cua » nghien cuu, nghiep cua, nghiep vua
hoa doanh » toan doanh, hoa dan
thong hoc » thuong hoc, tuong hoc, thong hoa
sach hoc » cach hoc, sach hoi, mach hoc
cong hoa » dong hoa, dong hoc, hang hoa
tu sach » thu sach, su sach, te sach
hoc lai » hoc dai, hoc bai, hoc lam
lai hoi » dai hoi, lai hoa, lai roi
va nhan » van nhan, ca nhan, va nha
va phan » van phan, va phat, va phap

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach hoc tap, nghien cua cong hoa doanh thong hoc lai hoi ((va nhan) OR (va phan)) van~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach hoc tap, nghien cua cong hoa doanh thong hoc lai hoi ((va nhan) OR (va phan)) van".
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien cua cong hoa doanh thong hoc lai hoi ((va nhan) OR (va phan)) van*.