Perhaps you should try some spelling variations:
22income distribution » income distribution, income distributions, income redistribution
time distributions » time distribution, size distributions, stable distributions
2f developing » f developing, 2.1 developing, self developing
70 developing » 10 developing, 40 developing, 160 developing
30 developing » 10 developing, 30 development
20 developing » 10 developing, 20 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 (time distributions)) %((2f developing) OR (((((70 developing) OR (30 developing))) OR (20 developing)))) countries%22.
• Adding a wildcard symbol may retrieve word variants: %((22income distribution) or (time distributions)) %((2f developing) or (((((70 developing) or (30 developing))) or (20 developing)))) countries%22*.