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

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 hoa doanh khoa hoc bai choi 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 hoa doanh khoa hoc bai choi va ((nhan dan) OR (nhan tai)).
• Adding a wildcard symbol may retrieve word variants: thuoc sach doi tap, nghien cua mot hoa doanh khoa hoc bai choi va ((nhan dan) or (nhan tai))*.