Perhaps you should try some spelling variations:
"international political economic series" » "international policy economic series", "international political economy series", "international ecological economics series", "international political economics series", "international political economic services"
"national poverty economic studies" » "national property economic studies", "national forestry economic studies", "national policy economic studies", "national poverty economic status"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("international political economic series") OR ("national poverty economic studies"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"international political economic series\") OR (\"national poverty economic studies\"))*".
• Removing quotes may allow a broader search: (( international political economic series ) OR ( national poverty economic studies ))*.