Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach tranh, cac nganh
thuyet hoa » thuyet va, huyet hoc
nganh kkxy » nganh ky
thuat van » thuat va, thuat ban, thuat vat
thuat san » thuat toan, thuat song, thuat lanh
y thuyet » ly thuyet, li thuyet, ly huyet
te sach » toc sach
tu sach » thu sach, su sach, tu cach

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 nganh y thuyet hoa hoc ) or ( tu sach nganh kkxy ((thuat van) OR (thuat san)) hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach nganh y thuyet hoa hoc ) OR ( tu sach nganh kkxy ((thuat van) OR (thuat san)) hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach nganh y thuyet hoa hoc ) or ( tu sach nganh kkxy ((thuat van) OR (thuat san)) hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( te sach nganh y thuyet hoa hoc ) or ( tu sach nganh kkxy ((thuat van) OR (thuat san)) hoc ))*.