Perhaps you should try some spelling variations:
"su sach dao nghe nguoi hop" » "su sach dao nghe nuoi hop", "su sach dao nghi nguoi hop", "su sach dao ngu nguoi hop", "su sach dao nghe nguoi ho", "su sach dao nghe nguoi hoan", "su sach dao nghe nguoi khoi", "su lanh dao nghe nguoi hop", "su sach day nghe nguoi hop", "su sach da nghe nguoi hop", "su sach dat nghe nguoi hop", "so sach dao nghe nguoi hop", "vu sach dao nghe nguoi hop"
"tu cach va nghe xu hoc" » "tu cac va nghe xu hoc", "tu cach van nghe xu hoc", "tu sach va nghe xu hoc", "tu cach ta nghe xu hoc", "tu cach ve nghe xu hoc", "tu cach va nghi xu hoc", "tu cach va nghe thu hoc", "tu cach va nghe tu hoc", "tu cach va nghe du hoc", "tu cach va nghe su hoc"

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: (("su sach dao nghe nguoi hop") or ("tu cach va nghe xu hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("su sach dao nghe nguoi hop") OR ("tu cach va nghe xu hoc")).
• Removing quotes may allow a broader search: (( su sach dao nghe nguoi hop ) or ( tu cach va nghe xu hoc )).
• Adding a wildcard symbol may retrieve word variants: (("su sach dao nghe nguoi hop") or ("tu cach va nghe xu hoc"))*.