Perhaps you should try some spelling variations:
learning inequality » learning quality, measuring inequality, deepening inequality
garding inequality » garding's inequality, hardy's inequality, rising inequality
hardy inequality » hardy's inequality, hardy inequalities, harnack inequality
wage » wave
earnings » warning

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: wage AND ((learning inequality) OR (((((garding inequality) OR (hardy inequality))) OR (earnings inequality)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "wage and ((learning inequality) or (((((garding inequality) OR (hardy inequality))) or (earnings inequality))))".
• Adding a wildcard symbol may retrieve word variants: wage and ((learning inequality) or (((((garding inequality) OR (hardy inequality))) or (earnings inequality))))*.