Perhaps you should try some spelling variations:
education inequality » educational inequality, education quality, educational quality
deepening inequality » explaining inequality, reducing inequality
measuring inequality » measuring quality
earnings » learning, 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 OR wave) AND ((education inequality) OR (((((((deepening inequality) OR (measuring inequality))) OR (harnack inequality))) OR (earnings inequality)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(wage OR wave) and ((education inequality) or (((((((deepening inequality) or (measuring inequality))) or (harnack inequality))) or (earnings inequality))))".
• Adding a wildcard symbol may retrieve word variants: (wage OR wave) and ((education inequality) or (((((((deepening inequality) or (measuring inequality))) or (harnack inequality))) or (earnings inequality))))*.