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