Perhaps you should try some spelling variations:
"practical differential equations" » "practical differentially equations", "fractional differential equations", "partial differential equations"
"racial differences equations" » "racial difference equations", "racial difference equation", "racial differentes situations", "regional differences equations"
"racial differential equations" » "radial differential equations", "fractal differential equations", "rail differential 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: (("racial differences equations") OR ((("racial differential equations") OR ("practical differential equations")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"racial differences equations\") or (((\"racial differential equations\") OR (\"practical differential equations\"))))".
• Removing quotes may allow a broader search: (( racial differences equations ) or ((( racial differential equations ) OR ( practical differential equations )))).
• Adding a wildcard symbol may retrieve word variants: (("racial differences equations") or ((("racial differential equations") OR ("practical differential equations"))))*.