Perhaps you should try some spelling variations:
"racial differentes situations" » "racial different situations", "racial differences situations", "crucial differences situations", "social differences situations"
"potential difference equations" » "potential differential equations", "potential differential equationss"
"racial difference equation" » "racial differential equation", "racial differential equations", "racial differences equation", "facial difference equation", "social difference equation"

Try widening your search to All Fields.

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: (((("racial difference equation") OR ("racial differentes situations"))) OR ("potential difference equations")).
• Removing quotes may allow a broader search: (((( racial difference equation ) or ( racial differentes situations ))) or ( potential difference equations )).
• Adding a wildcard symbol may retrieve word variants: (((("racial difference equation") or ("racial differentes situations"))) or ("potential difference equations"))*.