Perhaps you should try some spelling variations:
"so sach ki thuat do khi" » "so sach ki thuat o khi", "so sanh ki thuat do khi", "bo sach ki thuat do khi", "co sach ki thuat do khi", "so sach kinh thuat do khi", "so sach bai thuat do khi", "so sach kem thuat do khi", "so sach ki thuat doi khi", "so sach ki thuat do thi", "so sach ki thuat bo khi"
"tu sach ky thuat co khi" » "tu sach ky thuat o khi", "su sach ky thuat co khi", "te sach ky thuat co khi", "tu cach ky thuat co khi", "tu sac ky thuat co khi", "tu sach y thuat co khi", "tu sach ty thuat co khi"
"thu sach bac thuc co khi" » "thuat sach bac thuc co khi", "thuoc sach bac thuc co khi", "thu hoach bac thuc co khi", "thu sach bai thuc co khi", "thu sach dao thuc co khi", "thu sach xa thuc co khi", "thu sach bao thuc co khi", "thu sach bac thua co khi", "thu sach cach thuc co khi", "thu sach bac tuc co khi", "thu sach bac thuc cua 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 ki thuat do khi") or ((("tu sach ky thuat co khi") or ("thu sach bac thuc co khi"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("so sach ki thuat do khi") OR ((("tu sach ky thuat co khi") OR ("thu sach bac thuc co khi"))))*.
• Removing quotes may allow a broader search: (( so sach ki thuat do khi ) or ((( tu sach ky thuat co khi ) or ( thu sach bac thuc co khi ))))*.