Perhaps you should try some spelling variations:
sach ngan » sach ngon, sach nha, sach han
my thuat » ky thuat, ki thuat, va thuat
tranh ky » thanh ky, hanh ky, nganh ky
te sach » toc sach
ngan my » nhan my, nganh ma, nganh ky
thuat o » thuat do
tu canh » thu canh, tu chanh, tu can
o hoc » co hoc, mo hoc, so hoc
toan » tran

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach ngan my thuat o hoc ) OR ( tu canh ((tranh ky) OR (trinh ky)) thuat toan khoa ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach ngan my thuat o hoc ) or ( tu canh ((tranh ky) OR (trinh ky)) thuat toan khoa ))~".
• Adding a wildcard symbol may retrieve word variants: (( te sach ngan my thuat o hoc ) or ( tu canh ((tranh ky) OR (trinh ky)) thuat toan khoa ))*.