Perhaps you should try some spelling variations:
measuring inequality » measuring quality
learning inequality » earnings inequality, garding inequality, deepening 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 (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 (measuring inequality))) or (((learning quality) or (learning ability))))".
• Adding a wildcard symbol may retrieve word variants: wage and ((((learning inequality) OR (measuring inequality))) or (((learning quality) or (learning ability))))*.