Perhaps you should try some spelling variations:
sach tranh » canh tranh
sach danh » sach dao, sach kinh
kxy thuat » ky thuat, ki thuat, my thuat
thuat do » thuat o
toan hoc » toan khoa, van hoc, hoa hoc
tu sach » thu sach, su sach, te sach
y thuat » ky thuat, my thuat, ki thuat
do hoc » co hoc, do hoa, du 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: "\"((\\"tu ((sach danh) OR (sach dung)) y thuat do hoc\\") or (\\"tu sach tranh kxy thuat toan hoc\\"))\"".
• Removing quotes may allow a broader search: (( tu ((sach danh) OR (sach dung)) y thuat do hoc ) or ( tu sach tranh kxy thuat toan hoc )).