Perhaps you should try some spelling variations:
sach nhan » sach nha, sach han, cach nhanh
sach ngan » sach ngon, sach nha, sach han
kem thuat » kiem thuat, ky thuat, ki thuat
bao hanh » ban hanh, dao hanh, ban thanh
y thuat » ky thuat, my thuat, kxy thuat
thu bao » thu ban, thuat bao, thu thao
do hoc » co hoc, do hoa, du 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 nhan) OR (sach ngan)) y thuat do hoc ) or ( thu bao hanh kem thuat o hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te ((sach nhan) OR (sach ngan)) y thuat do hoc ) OR ( thu bao hanh kem thuat o hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te ((sach nhan) OR (sach ngan)) y thuat do hoc ) or ( thu bao hanh kem thuat o hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( te ((sach nhan) OR (sach ngan)) y thuat do hoc ) or ( thu bao hanh kem thuat o hoc ))*.