Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach tranh, sach danh
cac nganh » hoc nganh
nganh ky » nganh y, nganh xay, hanh ky
thuat so » thuat o, thuat co, thuat song
thuat do » thuat o
co sach » bo sach, cuon sach, hoc sach
o cac » o cao
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 ky thuat toan khoa ) or ( o cac nganh mac ((thuat so) OR (thuat do)) hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( co sach nganh ky thuat toan khoa ) OR ( o cac nganh mac ((thuat so) OR (thuat do)) hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( co sach nganh ky thuat toan khoa ) or ( o cac nganh mac ((thuat so) OR (thuat do)) hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( co sach nganh ky thuat toan khoa ) or ( o cac nganh mac ((thuat so) OR (thuat do)) hoc ))*.