Perhaps you should try some spelling variations:
"so sach bai nghiep dau hoc" » "so sach mai nghiep dau hoc", "so sach giai nghiep dau hoc", "so sach lam nghiep dau hoc", "so sach bai nghiep cau hoc", "so sach bai nghiep dai hoc", "so sach bai nghiem dau hoc", "so sach dao nghiep dau hoc", "so cac bai nghiep dau hoc", "so sach xa nghiep dau hoc", "so sanh bai nghiep dau hoc", "bo sach bai nghiep dau hoc", "co sach bai nghiep dau hoc", "so sach bai nghiep du hoc", "so sach bai nghiep dan hoc"
"su sac thai nghe xa hoc" » "su rac thai nghe xa hoc", "su sach tham nghe xa hoc", "su toc thai nghe xa hoc", "su sac thai nghe xay hoc", "su sac thai nghe va hoc", "su sac thai nghe xu hoc", "su sach thai nghe xa hoc", "su cac thai nghe xa hoc", "su xac thai nghe xa hoc", "su sac thai nghe xa hoi", "su sac thai nghe xa hoa"

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: (("so sach bai nghiep dau hoc") or ("su sac thai nghe xa hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("so sach bai nghiep dau hoc") OR ("su sac thai nghe xa hoc")).
• Removing quotes may allow a broader search: (( so sach bai nghiep dau hoc ) or ( su sac thai nghe xa hoc )).
• Adding a wildcard symbol may retrieve word variants: (("so sach bai nghiep dau hoc") or ("su sac thai nghe xa hoc"))*.