Perhaps you should try some spelling variations:
"su mach hoc lam nguoi" » "su mach hoc dao nguoi", "su mach hoc tay nguoi", "su cach hoc lam nguoi", "su dich hoc lam nguoi", "su anh hoc lam nguoi"
"su sach duoc lam nguoi" » "su sach duoc dao nguoi", "su sach duoc tay nguoi", "su sach dao lam nguoi", "su sach dung lam nguoi", "su sinh duoc lam nguoi", "su sach duoc pham nguoi", "su sach duoc ly nguoi", "su sach duoc li nguoi", "so sach duoc lam nguoi", "vu sach duoc lam nguoi"
"su sach nuoc lam nguoi" » "su sach nuoc dao nguoi", "su sach nuoc tay nguoi", "su cac nuoc lam nguoi", "su bach tuoc lam nguoi", "su dich nuoc lam nguoi", "su sach nuoc nam nguoi", "su sach nuoc luan nguoi", "su sach nguoc lai nguoi", "so sach nuoc lam nguoi", "vu sach nuoc lam 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: (("su mach hoc lam nguoi") or ((("su sach duoc lam nguoi") OR ("su sach nuoc lam nguoi"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("su mach hoc lam nguoi") OR ((("su sach duoc lam nguoi") OR ("su sach nuoc lam nguoi")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"su mach hoc lam nguoi\") or (((\"su sach duoc lam nguoi\") OR (\"su sach nuoc lam nguoi\"))))".
• Removing quotes may allow a broader search: (( su mach hoc lam nguoi ) or ((( su sach duoc lam nguoi ) OR ( su sach nuoc lam nguoi )))).
• Adding a wildcard symbol may retrieve word variants: (("su mach hoc lam nguoi") or ((("su sach duoc lam nguoi") OR ("su sach nuoc lam nguoi"))))*.