Perhaps you should try some spelling variations:
sach tranh » canh tranh
tranh kki » tranh cai
kki thuat » ki thuat, khoi thuat, ky thuat
sach dan » sach danh, sach dao, sach dat
thuat do » thuat o
thuat va » thuyet va, thuat xay, thuat bai
tu sach » thu sach, su sach, te sach
y thuat » ky thuat, my thuat, kxy thuat
do hoc » co hoc, do hoa, du hoc
va hoc » van hoc
dan y » dan ky, dan _, day y

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 dan y thuat do hoc ) or ( tu sach tranh kki thuat va hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach dan y thuat do hoc ) OR ( tu sach tranh kki thuat va hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach dan y thuat do hoc ) or ( tu sach tranh kki thuat va hoc ))*.