Perhaps you should try some spelling variations:
"differential equation" » "difference equations"
"differential equations" » "difference equationss"
"difference equationss" » "difference equations", "difference equation", "differenced equations"
"differences equations" » "difference equations", "difference equation", "differentes situations"

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: (((("differential equation") OR ("differential equations"))) OR ((("difference equationss") OR ("differences equations")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"differential equation\") or (\"differential equations\"))) or (((\"difference equationss\") OR (\"differences equations\"))))".
• Removing quotes may allow a broader search: (((( differential equation ) or ( differential equations ))) or ((( difference equationss ) OR ( differences equations )))).
• Adding a wildcard symbol may retrieve word variants: (((("differential equation") or ("differential equations"))) or ((("difference equationss") OR ("differences equations"))))*.