Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
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
cuu mot » cua mot, cuu mo, huu mot
mot hoc » mon hoc, mo hoc, mot goc
hoc mai » hoc ma, hoc dai, hoc bai
mai hoi » mai khoi, dai hoi, lai 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 cuu mot hoc doanh khoa hoc mai 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 cuu mot hoc doanh khoa hoc mai hoi va ((nhan dan) OR (nhan tai)).
• Adding a wildcard symbol may retrieve word variants: thuoc sach doi tap, nghien cuu mot hoc doanh khoa hoc mai hoi va ((nhan dan) or (nhan tai))*.