Perhaps you should try some spelling variations:
mau thuat » ma thuat, mau thuan, phau thuat
kki thuat » ki thuat, khoi thuat, ky thuat
sach mau » sach dau, sach dao, bach mai
thuat co » thuat o
sach kki » sach bai, sach kem, sach doi
thuat do » thuat o
so sach » so sanh, bo sach, co sach
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: (( so sach mau thuat co khi ) or ( so sach kki thuat do khi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach mau thuat co khi ) OR ( so sach kki thuat do khi )).
• Adding a wildcard symbol may retrieve word variants: (( so sach mau thuat co khi ) or ( so sach kki thuat do khi ))*.