Perhaps you should try some spelling variations:
income distributions » income redistribution, time distributions, size distributions
2f developing » 70 developing, 72 developing, self developing
f developing » self developing, turf developing, 7.2 developing

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: %((income distribution) OR (((income distributions) OR (discrete distributions)))) %((2f developing) OR (f developing)) countries%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((income distribution) or (((income distributions) OR (discrete distributions)))) %((2f developing) or (f developing)) countries%22".
• Adding a wildcard symbol may retrieve word variants: %((income distribution) or (((income distributions) OR (discrete distributions)))) %((2f developing) or (f developing)) countries%22*.