Perhaps you should try some spelling variations:
mac thuyet » hoc thuyet, suc thuyet, bai thuyet
cac nganh » hoc nganh
toc sach » hoc sach, doc sach, thuoc sach
tranh ky » trinh ky, thanh ky, hanh ky
thuat o » thuat do
te cac » tu cac, ve cac, te cao
va hoc » van hoc
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: (( ((te sach) OR (toc sach)) tranh ky thuat o hoc ) or ( te cac nganh mac thuyet va hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((te sach) OR (toc sach)) tranh ky thuat o hoc ) OR ( te cac nganh mac thuyet va hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((te sach) OR (toc sach)) tranh ky thuat o hoc ) or ( te cac nganh mac thuyet va hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( ((te sach) OR (toc sach)) tranh ky thuat o hoc ) or ( te cac nganh mac thuyet va hoc ))*.