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
tranh kki » tranh cai
kki thuat » ki thuat, khoi thuat, ky thuat
danh kxy » hanh ky, dan ky
tu sach » thu sach, su sach, te sach
o hoc » mo hoc, so hoc, y hoc
toan » tran

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sach danh kxy thuat ((o hoc) OR (co hoc)) ) or ( tu sach tranh kki thuat toan khoa ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach danh kxy thuat ((o hoc) OR (co hoc)) ) OR ( tu sach tranh kki thuat toan khoa ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach danh kxy thuat ((o hoc) OR (co hoc)) ) or ( tu sach tranh kki thuat toan khoa ))*".