Perhaps you should try some spelling variations:
sach nganh » sach tranh, cac nganh, sach danh
sach ngan » sach ngon, sach nha, sach han
kxy thuat » ky thuat, my thuat, ky thua
ki thuat » ky thuat
thuat o » thuat do
tu canh » thu canh, tu chanh, tu can
o hoc » co hoc, mo hoc, so hoc
tranh » trinh, thanh, tran
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: (( tu ((sach nganh) OR (sach ngan)) ki thuat o hoc ) OR ( tu canh tranh kxy thuat toan khoa ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu ((sach nganh) OR (sach ngan)) ki thuat o hoc ) or ( tu canh tranh kxy thuat toan khoa ))~".
• Adding a wildcard symbol may retrieve word variants: (( tu ((sach nganh) OR (sach ngan)) ki thuat o hoc ) or ( tu canh tranh kxy thuat toan khoa ))*.