Perhaps you should try some spelling variations:
"nhan dat su chinh tri kien." » "nhan dan su chinh tri kien." (Expand Search), "han dat su chinh tri kien." (Expand Search), "nhan dang su chinh tri kien." (Expand Search), "nhan dat so chinh tri kien." (Expand Search), "nhan dat cua chinh tri kien." (Expand Search), "nhan dat cuu chinh tri kien." (Expand Search), "nhan dat su chinh trien kien." (Expand Search), "nhan dat su chinh tri kinh." (Expand Search)
"nhan vat xu chinh tri vien." » "nhan vat tu chinh tri vien." (Expand Search), "nhan vat nu chinh tri vien." (Expand Search), "nhan vat xu thinh tri vien." (Expand Search), "nhan vat xu chinh tai vien." (Expand Search), "nhan vat xu chinh tri viet." (Expand Search), "nhan vat xu chinh tri chien." (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: (("nhan dat su chinh tri kien.") OR ("nhan vat xu chinh tri vien."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"nhan dat su chinh tri kien.\") OR (\"nhan vat xu chinh tri vien.\"))".
• Removing quotes may allow a broader search: (( nhan dat su chinh tri kien. ) OR ( nhan vat xu chinh tri vien. )).
• Adding a wildcard symbol may retrieve word variants: (("nhan dat su chinh tri kien.") OR ("nhan vat xu chinh tri vien."))*.