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 mai » hoc ma, hoc dai, hoc bai
mai hoi » mai khoi, dai hoi, lai hoi
va nhan » van nhan, va phan, va nha

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 mai hoi ((va nhan) OR (ca nhan)) 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 mai hoi ((va nhan) OR (ca nhan)) van".
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien cua cong hoa doanh thong hoc mai hoi ((va nhan) OR (ca nhan)) van*.