Perhaps you should try some spelling variations:
"dong tac bo sung tai lieu." » "cong tac bo sung tai lieu." (Expand Search), "dong tai bo sung tai lieu." (Expand Search), "dong bac bo sung tai lieu." (Expand Search), "dong tac bo dung tai lieu." (Expand Search), "dong tac bo dong tai lieu." (Expand Search), "dong tac bo vung tay lieu." (Expand Search), "dong tac bao sung tai lieu." (Expand Search), "dong lac bo sung tai lieu." (Expand Search)
"dong tac bo tung tai lieu." » "cong tac bo tung tai lieu." (Expand Search), "dong tai bo tung tai lieu." (Expand Search), "dong bac bo tung tai lieu." (Expand Search), "dong tac bo trung tai lieu." (Expand Search), "dong tac bo tuong tai lieu." (Expand Search), "dong tac bo dung tai lieu." (Expand Search), "dong tac son tung tai lieu." (Expand Search), "dong tac bo trong tai lieu." (Expand Search), "dong tac bao tung tai lieu." (Expand Search), "dong lac bo tung tai lieu." (Expand Search)

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"dong tac bo sung tai lieu.\") OR (\"dong tac bo tung tai lieu.\"))~".
• Removing quotes may allow a broader search: (( dong tac bo sung tai lieu. ) OR ( dong tac bo tung tai lieu. ))~.
• Adding a wildcard symbol may retrieve word variants: (("dong tac bo sung tai lieu.") OR ("dong tac bo tung tai lieu."))*.