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