Perhaps you should try some spelling variations:
"tu sach ki thuat do thi" » "tu sach ky thuat do thi", "tu sach ki thuat o thi", "thu sach ki thuat do thi", "su sach ki thuat do thi", "tu cach ki thuat do thi", "tu sach kinh thuat do thi", "tu sach bai thuat do thi", "tu sach kem thuat do thi"
"toc sach ky thut do khi" » "hoc sach ky thut do khi", "doc sach ky thut do khi", "thuoc sach ky thut do khi", "toc sac ky thut do khi", "toc sach y thut do khi", "toc sach ty thut do khi", "toc sach ky thuat do khi", "toc sach ky thu do khi", "toc sach kxy thuat do khi", "toc sach ky thuy do khi", "toc sach ky thuyet do khi", "toc sach ky thut doi khi", "toc sach ky thut co khi", "toc sach ky thut bo khi", "toc sach ky thut dco khi", "toc sach ky thut dbo khi"
"te sach ky thua o khi" » "te sac ky thua o khi", "te sach y thua o khi", "te sach ty thua o khi", "te sach ky thuat o khi", "te sach ky thu o khi", "te sach kxy thuat o khi", "te sach ky chua o khi", "te sach ky thua _ khi", "te sach ky thua co khi", "te sach ky thua 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: (((("te sach ky thua o khi") or ("toc sach ky thut do khi"))) or ("tu sach ki thuat do thi"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("te sach ky thua o khi") OR ("toc sach ky thut do khi"))) OR ("tu sach ki thuat do thi")).
• Removing quotes may allow a broader search: (((( te sach ky thua o khi ) or ( toc sach ky thut do khi ))) or ( tu sach ki thuat do thi )).
• Adding a wildcard symbol may retrieve word variants: (((("te sach ky thua o khi") or ("toc sach ky thut do khi"))) or ("tu sach ki thuat do thi"))*.