Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
nghien cua » nghien cuu, nghiep cua, nghiep vua
doanh khoa » toan khoa
hoc doanh » hoa doanh, hoc danh, hoc dan
sach doi » sach hoi, sach moi, sach dao
khoa hoc » hoa hoc
nhan dan » phan dau, gian dan
nhan tai » hang tai, van tai, toan tai
doi tap » doi tac, doi dap, doi tai
mot hoc » mon hoc, mo hoc, mot goc
hoc bai » hoc dai, hoc giai
bai hoi » bai choi, bai hoc, dai hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach doi tap, nghien cua mot hoc doanh khoa hoc bai hoi va ((nhan dan) or (nhan tai))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach doi tap, nghien cua mot hoc doanh khoa hoc bai hoi va ((nhan dan) OR (nhan tai)).
• Adding a wildcard symbol may retrieve word variants: thuoc sach doi tap, nghien cua mot hoc doanh khoa hoc bai hoi va ((nhan dan) or (nhan tai))*.