Perhaps you should try some spelling variations:
"te sach hoc lam nguoi" » "te sach hoc tay nguoi", "te cach hoc lam nguoi", "te sach hoi lam nguoi", "te sach duoc lam nguoi", "toc sach hoc lam nguoi"
"ke mach hoc lam nguoi" » "ke mach hoc tay nguoi", "ke cach hoc lam nguoi", "ke dich hoc lam nguoi", "ke anh hoc lam nguoi", "ke mach duoc lam nguoi", "ke hoach hoc lam nguoi"
"ke mach hoc dao nguoi" » "ke mach hoc cho nguoi", "ke cach hoc dao nguoi", "ke dich hoc dao nguoi", "ke anh hoc dao nguoi", "ke hoach hoc dao nguoi", "ke mach hoc dan nguoi", "ke mach hoc cao nguoi", "ke mach hoc dai nguoi"

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: (("te sach hoc lam nguoi") or ((("ke mach hoc lam nguoi") OR ("ke mach hoc dao nguoi"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("te sach hoc lam nguoi") OR ((("ke mach hoc lam nguoi") OR ("ke mach hoc dao nguoi")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"te sach hoc lam nguoi\") or (((\"ke mach hoc lam nguoi\") OR (\"ke mach hoc dao nguoi\"))))".
• Removing quotes may allow a broader search: (( te sach hoc lam nguoi ) or ((( ke mach hoc lam nguoi ) OR ( ke mach hoc dao nguoi )))).
• Adding a wildcard symbol may retrieve word variants: (("te sach hoc lam nguoi") or ((("ke mach hoc lam nguoi") OR ("ke mach hoc dao nguoi"))))*.