Perhaps you should try some spelling variations:
"te sach ki thuat co khi" » "te sach ki thuat o khi", "toc sach ki thuat co khi", "te sach kinh thuat co khi", "te sach bai thuat co khi", "te sach kem thuat co khi"
"tu sac ky thuat do khi" » "tu sac ky thuat o khi", "tu sach ky thuat do khi", "tu cac ky thuat do khi", "tu san ky thuat do khi", "tu sai ky thuat do khi", "tu sac ky thuat doi khi", "tu sac ky thuat do thi", "tu sac ky thuat dong khi"
"tu sac ky thuat bo khi" » "tu sac ky thuat bao khi", "tu sac ky thuat o khi", "tu sac ky thuat so khi", "tu sach ky thuat bo khi", "tu cac ky thuat bo khi", "tu san ky thuat bo khi", "tu sai ky thuat bo khi", "tu sac ky thuat bo chi", "tu sac ky thuat bo thi"

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: (("te sach ki thuat co khi") or ((("tu sac ky thuat do khi") OR ("tu sac ky thuat bo khi"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("te sach ki thuat co khi") OR ((("tu sac ky thuat do khi") OR ("tu sac ky thuat bo khi")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"te sach ki thuat co khi\") or (((\"tu sac ky thuat do khi\") OR (\"tu sac ky thuat bo khi\"))))".
• Removing quotes may allow a broader search: (( te sach ki thuat co khi ) or ((( tu sac ky thuat do khi ) OR ( tu sac ky thuat bo khi )))).
• Adding a wildcard symbol may retrieve word variants: (("te sach ki thuat co khi") or ((("tu sac ky thuat do khi") OR ("tu sac ky thuat bo khi"))))*.