Perhaps you should try some spelling variations:
22income distribution » income distribution, income redistribution, genome distribution
income distributions » income distribution, income redistribution, time distributions
7.3 developing » 3.3 developing, 4.3 developing, 5.3 developing
f developing » self developing, turf developing, 2.1 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: %((22income distribution) OR (income distributions)) %((((2((f developing) OR (7.3 developing))) OR (sel((f developing) OR (7.3 developing))))) OR (((f developing) OR (7.3 developing)))) countries%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((22income distribution) or (income distributions)) %((((2((f developing) OR (7.3 developing))) or (sel((f developing) OR (7.3 developing))))) or (((f developing) OR (7.3 developing)))) countries%22".
• Adding a wildcard symbol may retrieve word variants: %((22income distribution) or (income distributions)) %((((2((f developing) OR (7.3 developing))) or (sel((f developing) OR (7.3 developing))))) or (((f developing) OR (7.3 developing)))) countries%22*.