Perhaps you should try some spelling variations:
"tu sach thoi gian nguoi" » "tu cach thoi gian nguoi", "tu sach hoi gian nguoi", "tu sach tham gian nguoi", "thu sach thoi gian nguoi", "te sach thoi gian nguoi"
"su sach toc tay nguoi" » "su sach toc toc nguoi", "su sach toc dao nguoi", "su bach tuoc tay nguoi", "su sach duoc tay nguoi", "su sach nuoc tay nguoi", "so sach toc tay nguoi", "vu sach toc tay nguoi", "su sach toc thai nguoi"
"tu mach hoc gian nguoi" » "tu cach hoc gian nguoi", "tu dich hoc gian nguoi", "tu anh hoc gian nguoi", "tu mach hoc giao nguoi", "tu mach hoc giai nguoi", "tu mach hoc gia nguoi", "tu manh hoc gian nguoi", "tu hach hoc gian nguoi"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("tu mach hoc gian nguoi") or ("tu sach thoi gian nguoi"))) or ("su sach toc tay nguoi"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("tu mach hoc gian nguoi") OR ("tu sach thoi gian nguoi"))) OR ("su sach toc tay nguoi")).
• Removing quotes may allow a broader search: (((( tu mach hoc gian nguoi ) or ( tu sach thoi gian nguoi ))) or ( su sach toc tay nguoi )).
• Adding a wildcard symbol may retrieve word variants: (((("tu mach hoc gian nguoi") or ("tu sach thoi gian nguoi"))) or ("su sach toc tay nguoi"))*.