Perhaps you should try some spelling variations:
"partial differential equation" » "partial difference equations"
"spatial differential equations" » "spatial difference equationss", "spatial differentials equations", "special differential equations", "optimal differential equations"
"partial difference equationss" » "partial difference equations", "partial difference equation", "partial differenced equations", "potential difference equationss", "racial differences equationss"
"spatial differences equations" » "spatial difference equations", "spatial difference equation", "spatial differentes situations", "racial differences equations", "social differences equations", "national differences equations"

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