Perhaps you should try some spelling variations:
kxy thuat » ki thuat, my thuat, ky thua
sach kxy » sach xa, sach kem, sac ky
thuat co » thuat o
thuat do » thuat o
te sach » toc sach
tu sach » thu sach, su sach, tu cach
sach ky » sac ky, sach y, sach ty
do khi » doi khi, do thi, bo khi

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 kxy thuat co khi ) or ( tu sach ky thuat do khi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach kxy thuat co khi ) OR ( tu sach ky thuat do khi )).
• Adding a wildcard symbol may retrieve word variants: (( te sach kxy thuat co khi ) or ( tu sach ky thuat do khi ))*.