Perhaps you should try some spelling variations:
income distributions » income redistribution, time distributions, discrete distributions
genome distribution » genomic distribution, gene distribution, monomer distribution
self developing » relief developing, self development, level 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: %((((income distribution) OR (genome distribution))) OR (income distributions)) %self developing countries%22.
• Adding a wildcard symbol may retrieve word variants: %((((income distribution) or (genome distribution))) or (income distributions)) %self developing countries%22*.