Perhaps you should try some spelling variations:
kxmy thuat » kxy thuat, my thuat
sach kxmy » sach kem
thuat co » thuat do
tu sach » thu sach, tu cach, vu sach
sach ki » sach kinh, sach bai, sach kem
thuat o » thuat do
su sach » so sach, vu sach
te sach » toc sach
sach ky » sac ky, sach y, sach ty
co khai » cao khai, co khi, co hai
o khi » co khi, bo khi

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

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