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

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sach y thuat do khi ) or ( so sach kxy thuat do khi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach y thuat do khi ) OR ( so sach kxy thuat do khi )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach y thuat do khi ) or ( so sach kxy thuat do khi ))*.