Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
trinh kxy » trinh ky, trinh ly, trinh ke
kxy thuat » ky thuat, ki thuat, my thuat
ngan hay » ngan han, ngan hang, nganh xay
thu canh » thuc hanh, thu cong, thu ban
toan hoc » toan khoa, van hoc, hoa hoc
tu sach » thu sach, su sach, te sach
ngan ky » nganh ky, nhan ky, nganh ke
thuat o » thuat do
o hoc » co hoc, mo hoc, so 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 ((ngan ky) OR (ngan hay)) thuat o hoc ) or ( thu canh trinh kxy thuat toan hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach ((ngan ky) OR (ngan hay)) thuat o hoc ) OR ( thu canh trinh kxy thuat toan hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tu sach ((ngan ky) OR (ngan hay)) thuat o hoc ) or ( thu canh trinh kxy thuat toan hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( tu sach ((ngan ky) OR (ngan hay)) thuat o hoc ) or ( thu canh trinh kxy thuat toan hoc ))*.