Perhaps you should try some spelling variations:
sach ngan » sach ngon, sach nha, sach han
sach manh » sach danh, sach tranh, cach mang
toan hoc » toan khoa, van hoc, hoa hoc
so sach » so sanh, bo sach, co sach
y thuat » my thuat, kxy thuat, ki thuat
manh ky » hanh ky, minh ky, manh duy
ngan y » nganh y, nhan y, nganh ky

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach ngan y thuat toan hoc ) OR ( so sach manh ky thuat toan hoc ))~.
• Adding a wildcard symbol may retrieve word variants: (( so sach ngan y thuat toan hoc ) or ( so sach manh ky thuat toan hoc ))*.