Perhaps you should try some spelling variations:
"public administration" » "publico administration" (Expand Search), "publicos administration" (Expand Search), "public administracao" (Expand Search)
"publica administration" » "publicoa administration" (Expand Search), "publicosa administration" (Expand Search), "publica administracao" (Expand Search)
"publicas administration" » "publicoas administration" (Expand Search), "publicosas administration" (Expand Search), "publicas administracao" (Expand Search), "publico administration" (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: "((\"public administration\") OR (((\"publica administration\") OR (\"publicas administration\"))))~".
• Removing quotes may allow a broader search: (( public administration ) OR ((( publica administration ) OR ( publicas administration ))))~.
• Adding a wildcard symbol may retrieve word variants: (("public administration") OR ((("publica administration") OR ("publicas administration"))))*.