Perhaps you should try some spelling variations:
"tinh dung luan van hieu soat" » "trinh dung luan van hieu soat", "tin dung luan van hieu soat", "tinh quang luan van hieu soat", "tinh dung luan van hieu suat", "tinh dung luan van hieu hoat", "tinh dung luan van hieu luat", "tinh dung luan cao hieu soat", "tinh dung lan van hieu soat"
"tinh nang quan van kien soat" » "trinh nang quan van kien soat", "tin nang quan van kien soat", "tich nang quan van kien soat", "tinh ban quan van kien soat", "tinh nang suat van kien soat", "tinh nang quan van kiem soat", "tinh nang quan van bien soan", "tinh nang quan van kien hoa", "tinh nang quan va kien soat", "tinh nang quan luan kien soat", "tinh nang quan doan kien soat", "tinh nang quan van tien soat", "tinh nang quan van hien soat", "tinh nang quan van chien soat"

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: (("tinh dung luan van hieu soat") or ("tinh nang quan van kien soat"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("tinh dung luan van hieu soat") OR ("tinh nang quan van kien soat")).
• Removing quotes may allow a broader search: (( tinh dung luan van hieu soat ) or ( tinh nang quan van kien soat )).
• Adding a wildcard symbol may retrieve word variants: (("tinh dung luan van hieu soat") or ("tinh nang quan van kien soat"))*.