Perhaps you should try some spelling variations:
22income distribution » income distribution, income redistribution, genome distribution
income distributions » income distribution, income redistribution, time distributions
20 development » 10 development
72 developing » 7.2 developing, 762 developing, 2 developing
10 developing » 10 development

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 distributions)) %((72 developing) OR (((10 developing) OR (((20 developing) OR (20 development)))))) countries%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((22income distribution) or (income distributions)) %((72 developing) or (((10 developing) or (((20 developing) OR (20 development)))))) countries%22".
• Adding a wildcard symbol may retrieve word variants: %((22income distribution) or (income distributions)) %((72 developing) or (((10 developing) or (((20 developing) OR (20 development)))))) countries%22*.