Perhaps you should try some spelling variations:
measuring inequality » measuring quality
deepening inequality » explaining inequality, earnings inequality, reducing inequality
learning inequality » earnings inequality, garding inequality, reducing inequality
learning ability » learning disability, learning activity, learning about
wage » wave

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