Perhaps you should try some spelling variations:
"cong trinh luan van thu cong cu duong" » "cong trinh luat van thu cong cu duong", "cong trinh quan van thu cong cu duong", "cong trinh toan van thu cong cu duong", "cong trinh luan van thu cong cau duong", "cong trinh luan van thu cong cu dung", "cong trinh luan van thu cong co duong", "cong trinh luan van thu chung cu duong"
"cong trinh han van tai cong chat luong" » "cong trinh quan van tai cong chat luong", "cong trinh han van tai cong nhat luong", "cong trinh han van tai cong cua luong", "cong trinh han van tai cong ha luong", "cong trinh phan van tai cong chat luong", "cong trinh nhan van tai cong chat luong", "cong trinh hanh van tai cong chat luong", "cong trinh han von tai cong chat luong", "cong trinh han van tuan cong chat luong"

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: (("cong trinh han van tai cong chat luong") or ("cong trinh luan van thu cong cu duong"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("cong trinh han van tai cong chat luong") OR ("cong trinh luan van thu cong cu duong")).
• Removing quotes may allow a broader search: (( cong trinh han van tai cong chat luong ) or ( cong trinh luan van thu cong cu duong )).
• Adding a wildcard symbol may retrieve word variants: (("cong trinh han van tai cong chat luong") or ("cong trinh luan van thu cong cu duong"))*.