Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
sach nhan » sach nha, sach han, sach ngan
thanh kem » hanh kem, thanh ke, thanh ket
kem thuat » kiem thuat, ky thuat, ki thuat
tu sach » thu sach, su sach, te sach
y thuat » ky thuat, my thuat, kxy thuat
thuat o » thuat do
do hoc » do hoa, du hoc, mo hoc
tu ban » thu ban, te ban
o hoc » mo hoc, so hoc, y hoc

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 nhan y thuat ((do hoc) OR (co hoc)) ) or ( tu ban thanh kem thuat o hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach nhan y thuat ((do hoc) OR (co hoc)) ) OR ( tu ban thanh kem thuat o hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach nhan y thuat ((do hoc) OR (co hoc)) ) or ( tu ban thanh kem thuat o hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu sach nhan y thuat ((do hoc) OR (co hoc)) ) or ( tu ban thanh kem thuat o hoc ))*.