Perhaps you should try some spelling variations:
22income distribution » income redistribution, genome distribution, income distributional
income distributions » income redistribution, time distributions, discrete distributions
2f developing » f developing, 72 developing, self developing
70 developing » 10 developing, 20 developing, 30 developing

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: %((((22income distribution) OR (income distribution))) OR (income distributions)) %((2f developing) OR (70 developing)) countries%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((((22income distribution) OR (income distribution))) or (income distributions)) %((2f developing) or (70 developing)) countries%22".
• Adding a wildcard symbol may retrieve word variants: %((((22income distribution) OR (income distribution))) or (income distributions)) %((2f developing) or (70 developing)) countries%22*.