Perhaps you should try some spelling variations:
learning inequality » learning quality, garding inequality, measuring inequality
hardy's inequality » hardy inequality, holder's inequality, 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 (earnings inequality))) OR (hardy's inequality)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "wage and ((((learning inequality) OR (earnings inequality))) or (hardy's inequality))".
• Adding a wildcard symbol may retrieve word variants: wage and ((((learning inequality) OR (earnings inequality))) or (hardy's inequality))*.