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