Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach tranh, cac nganh
thuyet hoa » thuyet va, huyet hoc
ki thuyet » li thuyet, gia thuyet, bai thuyet
kxy thuat » ki thuat, my thuat, ky thua
nganh ki » nganh ky, nganh ke, nganh vi
thu sach » tu sach, thuat sach, thuoc sach
te sach » toc sach
van hoc » van hoa

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