Perhaps you should try some spelling variations:
"tu sach ki thuat do thi" » "tu sach ki thuat o thi", "tu sach kinh thuat do thi", "tu sach bai thuat do thi", "tu sach kem thuat do thi", "thu sach ki thuat do thi", "su sach ki thuat do thi", "tu cach ki thuat do thi"
"hoc sach ky thuat bo chi" » "hoc sinh ky thuat bo chi", "hoc cac ky thuat bo chi", "hoc anh ky thuat bo chi", "hoc sach ky thuat bao chi", "hoc sach ky thuat o chi", "hoc sach ky thuat co chi", "hoc sac ky thuat bo chi", "hoc sach y thuat bo chi", "hoc sach kem thuat bo chi", "hoc sach ky thuat ho chi", "hoc sach ky thuat bo cai"
"te sach ty thua o khi" » "te sach y thua o khi", "te sach tu thua o khi", "te sach thu thua o khi", "toc sach ty thua o khi", "te sach ky thua o khi", "te sach ty nhua o khi", "te sach ty thuat o khi", "te sach ty chua o khi", "te sach ty thua _ khi", "te sach ty thua co khi", "te sach ty 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 ty 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 ty 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 ty 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 ty thua o khi") or ("hoc sach ky thuat bo chi"))) or ("tu sach ki thuat do thi"))*.