Perhaps you should try some spelling variations:
bai thuat » giai thuat, bai thuyet, ki thuat
sach bai » sach dao, cac bai, sach xa
thuat do » thuat o
thuat co » thuat o
tu sach » thu sach, su sach, te sach
do khi » doi khi, do thi, bo khi
tu bac » tu ban, tu cac, tu bat
bac ky » cac ky, ban ky, sac ky

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 bai thuat do khi ) or ( tu bac ky thuat co khi ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach bai thuat do khi ) OR ( tu bac ky thuat co khi ))*.