Perhaps you should try some spelling variations:
kki thuat » ki thuat, khoi thuat, mi thuat
thuat co » thuat o
thuat do » thuat o
tu cach » tu cac
te sach » toc sach
su sach » so sach, vu sach
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: (( ((tu cach) or (te sach)) kki thuat co khi ) or ( su sach ky thuat do khi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((tu cach) OR (te sach)) kki thuat co khi ) OR ( su sach ky thuat do khi )).
• Adding a wildcard symbol may retrieve word variants: (( ((tu cach) or (te sach)) kki thuat co khi ) or ( su sach ky thuat do khi ))*.