Perhaps you should try some spelling variations:
sach tranh » canh tranh
sach danh » sach dao, sach dung, sach kinh
kxy thuat » ky thuat, ki thuat, my thuat
toan hoc » toan khoa, van hoc, hoa hoc
su sach » so sach, vu sach
y thuat » ky thuat, my thuat, ki thuat
danh y » anh y, hanh y, dan y
do hoc » do hoa, du hoc, mo hoc

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "\"((\\"su sach danh y thuat ((do hoc) OR (co hoc))\\") or (\\"su sach tranh kxy thuat toan hoc\\"))\"".
• Removing quotes may allow a broader search: (( su sach danh y thuat ((do hoc) OR (co hoc)) ) or ( su sach tranh kxy thuat toan hoc )).