Perhaps you should try some spelling variations:
"su sach y thuat doc khi" » "su sach y thuat duoc khi", "su sach y thuat do khi", "su sach y thuat doi khi", "so sach y thuat doc khi", "vu sach y thuat doc khi", "su sach my thuat doc khi", "su sach kxy thuat doc khi", "su sach ki thuat doc khi", "su sach y thuat hoc khi", "su sach y thuat hoc khoi"
"su sach tu thuat bo thi" » "su sach thu thuat bo thi", "su sach te thuat bo thi", "su sach tu thua bo thi", "su sach tu thuat bao thi", "su sach tu thuat do thi", "su sach tu thuat co thi", "so sach tu thuat bo thi", "vu sach tu thuat bo thi", "su cach tu thuat bo thi", "su sach ty thuat bo thi", "su sach tu thuat bo thit", "su sach tu thuat bo tai"
"bo sach ky thuat o khi" » "co sach ky thuat o khi", "hoc sach ky thuat o khi", "bo sac ky thuat o khi", "bo sach ty thuat o khi", "bo sach kem thuat o khi", "bo sach ky thuat do khi", "bo sach kmy thuat o khi", "bo sach kkxy thuat o khi", "bo sach kki thuat o khi", "bo sach ky thuat co khi", "bo 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: (("bo sach ky thuat o khi") or ((("su sach y thuat doc khi") or ("su sach tu thuat bo thi"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("bo sach ky thuat o khi") OR ((("su sach y thuat doc khi") OR ("su sach tu thuat bo thi")))).
• Removing quotes may allow a broader search: (( bo sach ky thuat o khi ) or ((( su sach y thuat doc khi ) or ( su sach tu thuat bo thi )))).
• Adding a wildcard symbol may retrieve word variants: (("bo sach ky thuat o khi") or ((("su sach y thuat doc khi") or ("su sach tu thuat bo thi"))))*.