Perhaps you should try some spelling variations:
"tu sach ki thuat co khi" » "tu sach ki thuat do khi", "thu sach ki thuat co khi", "su sach ki thuat co khi", "tu cach ki thuat co khi", "tu sach kinh thuat co khi", "tu sach bai thuat co khi", "tu sach kem thuat co khi", "tu sanh ki thuat co khi", "tu bach ki thuat co khi", "tu sach ki thuat cbo khi"
"tu sac ky thuat co khi" » "tu sac ky thuat do khi", "tu cac ky thuat co khi", "tu san ky thuat co khi", "tu bac ky thuat co khi", "tu sai ky thuat co khi", "tu sac ky thuat cbo khi"
"te sach ky thuat o khi" » "toc sach ky thuat o khi", "te sach y thuat o khi", "te sach ty thuat o khi", "te sach kem thuat o khi", "te sach ky thuat do khi", "te sach ky thuat bo khi"

Try widening your search to All Fields.

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