Perhaps you should try some spelling variations:
"hoc sach ky thuat bo chi" » "hoc sach ky thuat bao chi", "hoc sach ky thuat o chi", "hoc sach ky thuat co chi", "hoc sinh ky thuat bo chi", "hoc cac ky thuat bo chi", "hoc anh ky thuat bo chi", "hoc sac ky thuat bo chi", "hoc sach y thuat bo chi", "hoc sach ty thuat bo chi", "hoc sach ky thut bo chi", "hoc sach kxy thuatt bo chi", "hoc sach my thuatt bo chi", "hoc sach ky thuat ho chi", "hoc sach ky thuat bo cai"
"tu sach ki 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"
"te sach ky thua o khi" » "toc 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 thu o khi", "te sach kxy thuat o khi", "te sach my thuat o khi", "te sach ky 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"

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 ("hoc sach ky thuat bo chi"))) 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 ("hoc sach ky thuat bo chi"))) OR ("tu sach ki thuat do thi")).
• Removing quotes may allow a broader search: (((( te sach ky thua o khi ) or ( hoc sach ky thuat bo chi ))) or ( tu sach ki thuat do thi )).
• Adding a wildcard symbol may retrieve word variants: (((("te sach ky thua o khi") or ("hoc sach ky thuat bo chi"))) or ("tu sach ki thuat do thi"))*.