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 bac bao dung tai lieu." » "cong bac bao dong tai lieu." (Expand Search), "cong bac bao dung doi lieu." (Expand Search), "cong bac bao dung tin lieu." (Expand Search), "chong bac bao dung tai lieu." (Expand Search), "dong bac bao dung tai lieu." (Expand Search), "cong bao bao dung tai lieu." (Expand Search), "cong bac bao duong tai lieu." (Expand Search), "cong bac bao dang tai lieu." (Expand Search), "cong bac bo dung tai lieu." (Expand Search), "cong tac bao dung tai lieu." (Expand Search), "cong cac bao 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 bac bao dung tai lieu."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"cong tac mo dung tai lieu.\") OR (\"cong bac bao dung tai lieu.\"))".
• Removing quotes may allow a broader search: (( cong tac mo dung tai lieu. ) OR ( cong bac bao dung tai lieu. )).
• Adding a wildcard symbol may retrieve word variants: (("cong tac mo dung tai lieu.") OR ("cong bac bao dung tai lieu."))*.