Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach danh, cach nhanh
sach tranh » canh tranh
cac nganh » hoc nganh
mac thuat » cac thuat, ma thuat, my thuat
thuat o » thuat do
o cac » o cao
o hoc » co hoc, mo hoc, so hoc
toan » tran

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( co ((sach nganh) OR (sach tranh)) ky thuat toan khoa ) or ( o cac nganh mac thuat o hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( co ((sach nganh) OR (sach tranh)) ky thuat toan khoa ) OR ( o cac nganh mac thuat o hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( co ((sach nganh) OR (sach tranh)) ky thuat toan khoa ) or ( o cac nganh mac thuat o hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( co ((sach nganh) OR (sach tranh)) ky thuat toan khoa ) or ( o cac nganh mac thuat o hoc ))*.