Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
sach ngan » sach ngon, sach han, sach nang
thuat ban » thuat bai, thuat bao, thuat san
thuat do » thuat o
trinh ly » trinh ky, trinh do, trinh tu
ly thuat » my thuat, ly thuyet, kxy thuat
tu canh » thu canh, tu chanh, tu can
ban hoc » bang hoc, van hoc, bai hoc
do hoc » co hoc, do hoa, du 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 ngan) OR (sach nha)) ky thuat do hoc ) or ( tu canh trinh ly thuat ban hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te ((sach ngan) OR (sach nha)) ky thuat do hoc ) OR ( tu canh trinh ly thuat ban hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te ((sach ngan) OR (sach nha)) ky thuat do hoc ) or ( tu canh trinh ly thuat ban hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( te ((sach ngan) OR (sach nha)) ky thuat do hoc ) or ( tu canh trinh ly thuat ban hoc ))*.