Perhaps you should try some spelling variations:
"cong tac mo dung tai lieu." » "cong tac mo dong tai lieu." (Expand Search), "cong tac mo dung doi lieu." (Expand Search), "cong tac mo dung tin lieu." (Expand Search), "cong tac my dung tai lieu." (Expand Search), "cong tac mo rung tai lieu." (Expand Search), "cong tac mo cung tai lieu." (Expand Search), "cong toc mo dung tai lieu." (Expand Search)
"cong bao bo dung tai lieu." » "cong bao bo dong tai lieu." (Expand Search), "cong bao bo dung doi lieu." (Expand Search), "cong bao bo dung tin lieu." (Expand Search), "dong bao bo dung tai lieu." (Expand Search), "cong giao bo dung tai lieu." (Expand Search), "thong bao bo dung tai lieu." (Expand Search), "cong bao bo duong tai lieu." (Expand Search), "cong bao bao dung tai lieu." (Expand Search), "cong bao bo sung tai lieu." (Expand Search), "cong bao boi dung tai lieu." (Expand Search), "cong bao bi dung tai lieu." (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 mo dung tai lieu.") OR ("cong bao bo dung tai lieu."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"cong tac mo dung tai lieu.\") OR (\"cong bao bo dung tai lieu.\"))".
• Removing quotes may allow a broader search: (( cong tac mo dung tai lieu. ) OR ( cong bao bo dung tai lieu. )).
• Adding a wildcard symbol may retrieve word variants: (("cong tac mo dung tai lieu.") OR ("cong bao bo dung tai lieu."))*.