Perhaps you should try some spelling variations:
nghien hieu » nghiep hieu, thien hieu, hien hieu
doanh khoa » toan khoa
goc doanh » hoa doanh, voi doanh, von doanh
sach hoc » cach hoc, sach hoi, mach hoc
khoa hoc » hoa hoc
phan van » pham van, thanh van, luan van
tu sach » thu sach, su sach, te sach
hoc tai » hoc dai, hoc tap, hoc bai
hoc mai » hoc ma, hoc dai, hoc bai
mai hoi » mai khoi, dai hoi, lai hoi
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 tai, ((nghien hieu) OR (nghe hieu)) mot goc doanh khoa hoc mai hoi va phan van~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach hoc tai, ((nghien hieu) OR (nghe hieu)) mot goc doanh khoa hoc mai hoi va phan van".
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tai, ((nghien hieu) OR (nghe hieu)) mot goc doanh khoa hoc mai hoi va phan van*.