Perhaps you should try some spelling variations:
"political economic" » "political economy", "ecological economics"
"political ecology" » "political economy", "political sociology"
"policy economic" » "policy economics", "policy macroeconomic"

Try widening your search to All Fields.

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("political economic") OR ("political ecology"))) OR ("policy economic")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"political economic\") OR (\"political ecology\"))) or (\"policy economic\"))".
• Removing quotes may allow a broader search: (((( political economic ) OR ( political ecology ))) or ( policy economic )).
• Adding a wildcard symbol may retrieve word variants: (((("political economic") OR ("political ecology"))) or ("policy economic"))*.