Perhaps you should try some spelling variations:
"cong tac luan van." » "cong thac luan van." (Expand Search), "cong bac luan van." (Expand Search), "cong toc luan van." (Expand Search), "dong tac luan van." (Expand Search)
"cong tac quan van." » "cong tac van van." (Expand Search), "cong tac quan hoan." (Expand Search), "cong tac quan lang." (Expand Search), "cong tac san van." (Expand Search), "cong tac luan van." (Expand Search), "cong tac quan ban." (Expand Search), "cong tac quan han." (Expand Search), "dong tac quan van." (Expand Search)
"cong tac quan va." » "cong tac van va." (Expand Search), "cong tac luan va." (Expand Search), "cong tac quan ba." (Expand Search), "cong tac quan ha." (Expand Search), "dong tac quan va." (Expand Search)

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 tac luan van.") OR ((("cong tac quan van.") OR ("cong tac quan va."))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"cong tac luan van.\") OR (((\"cong tac quan van.\") OR (\"cong tac quan va.\"))))".
• Removing quotes may allow a broader search: (( cong tac luan van. ) OR ((( cong tac quan van. ) OR ( cong tac quan va. )))).
• Adding a wildcard symbol may retrieve word variants: (("cong tac luan van.") OR ((("cong tac quan van.") OR ("cong tac quan va."))))*.