Perhaps you should try some spelling variations:
"trinh dung luan van hien soat" » "trinh dung luan van thien hoat", "trinh dung luan van kiem soat", "trinh dung luan van bien soan", "trinh dung luan van tien soat", "trinh dung quan van hien soat", "trinh dung lan van hien soat"
"tinh dung dam van hieu hoa" » "tin dung dam van hieu hoa", "tinh quang dam van hieu hoa", "tinh huong dam van hieu hoa", "tinh dung dat van hieu hoa", "tinh dung lam van hieu hoa", "tinh dung dan van hieu hoa", "tinh dung dam cao hieu hoa", "tinh dung dam van tieu hoa", "tinh dung dam van dieu hoa", "tinh dung dam van hiep hoa", "tinh dung dao van hieu hoa", "tinh dung nam van hieu hoa", "tinh dung pham van hieu hoa"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("trinh dung luan van hien soat") or ("tinh dung dam van hieu hoa"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("trinh dung luan van hien soat") OR ("tinh dung dam van hieu hoa"))*.
• Removing quotes may allow a broader search: (( trinh dung luan van hien soat ) or ( tinh dung dam van hieu hoa ))*.