Perhaps you should try some spelling variations:
"cong tac ba duong tai lieu." » "cong tac ba duong thai lieu." (Expand Search), "cong tac ba duong dai lieu." (Expand Search), "cong tac ba duong thi lieu." (Expand Search), "cong tac xa duong tai lieu." (Expand Search), "cong tac bach duong tai lieu." (Expand Search), "cong tac hai duong tai lieu." (Expand Search), "cong tac ban duong tai lieu." (Expand Search), "cong tac bao duong tai lieu." (Expand Search), "cong thac ba duong tai lieu." (Expand Search), "dong tac ba duong tai lieu." (Expand Search)
"cong tac bo dung tai lieu." » "cong tac bo dong tai lieu." (Expand Search), "cong tac bo dung doi lieu." (Expand Search), "cong tac bo dung tin lieu." (Expand Search), "cong tac bo duong tai lieu." (Expand Search), "cong tac bao dung tai lieu." (Expand Search), "cong tac bo sung tai lieu." (Expand Search), "cong bac bo dung tai lieu." (Expand Search), "cong lac bo dung tai lieu." (Expand Search), "dong tac bo 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 bo dung tai lieu.") OR ("cong tac ba duong tai lieu."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"cong tac bo dung tai lieu.\") OR (\"cong tac ba duong tai lieu.\"))".
• Removing quotes may allow a broader search: (( cong tac bo dung tai lieu. ) OR ( cong tac ba duong tai lieu. )).
• Adding a wildcard symbol may retrieve word variants: (("cong tac bo dung tai lieu.") OR ("cong tac ba duong tai lieu."))*.