Perhaps you should try some spelling variations:
"cong trinh luan van tien cong chat luong" » "cong trinh luat van tien cong chat luong", "cong trinh quan van tien cong chat luong", "cong trinh han van tien cong chat luong", "cong trinh luan van thien cong chat luong", "cong trinh luan van trien cong chat luong", "cong trinh luan van tien luong chat luong", "cong trinh luan van tien cong nhat luong", "cong trinh luan van tien cong cua luong", "cong trinh luan van tien cong ha luong", "cong trinh luan toan tien cong chat luong", "cong trinh luan van hieu cong chat luong", "cong trinh luan van tuan cong chat luong"
"cong trinh luan van nhiet dong chan duong" » "cong trinh luat van nhiet dong chan duong", "cong trinh quan van nhiet dong chan duong", "cong trinh han van nhiet dong chan duong", "cong trinh luan van nhiet dong chan dung", "cong trinh luan van nhiet dong han duong", "cong trinh luan van nhiet dong chan thuong", "cong trinh luan va nhiet dong chan duong", "cong trinh luan dan nhiet dong chan duong", "cong trinh luan van thiet dong chan duong", "cong trinh luan van nhiet dong chuan duong", "cong trinh luan van nhiet jong chan duong", "cong trinh luan van nhiet dong chen duong"

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