Perhaps you should try some spelling variations:
"african countries and political economy." » "rich countries and political economy.", "african countries and political economic."
"american cities and ecological economics." » "african cities and ecological economics.", "american countries and ecological economics.", "american studies and ecological economics.", "american cities and technological economics.", "american cities and ecological economic."

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: (("african countries and political economy.") or ("american cities and ecological economics."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("african countries and political economy.") OR ("american cities and ecological economics.")).
• Removing quotes may allow a broader search: (( african countries and political economy. ) or ( american cities and ecological economics. )).
• Adding a wildcard symbol may retrieve word variants: (("african countries and political economy.") or ("american cities and ecological economics."))*.