Perhaps you should try some spelling variations:
"tinh quang tuan van kiem soat" » "tinh quang thanh van kiem soat", "tinh quan luan van kiem soat", "tinh quang cua van kiem soat", "tinh quang tuan van kiem toan", "tinh quang luan van kiem soat", "tinh quang tran van kiem soat", "tinh quang tan van kiem soat", "tinh quang tuan va kiem soat", "tinh quang tuan van kien soat", "tinh quang tuan van hien soat"
"trinh dung ltan van hieu suat" » "trinh dung luan van hieu suat", "trinh dung tai van hieu suat", "trinh dung nhan van hieu suat", "trinh dung ltan van hieu luat", "trinh dung ltan van hieu qua", "trinh dung tan van hieu suat", "trinh dung lan van hieu suat", "trinh dung ltan cao hieu suat"

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