Perhaps you should try some spelling variations:
"motor neurone disease" » "motor neuronal disease", "motor neutrone disease", "motor neuroe disease", "motor neuronale disease"
"motor neuron disease" » "motor neutron disease", "motor neuro disease", "motor neuronal disease"
"motor neurons disease" » "motor neutrons disease", "motor neuros disease", "motor neuronals disease", "motor neuronal disease"
"motor neutrons disease" » "motor neutron disease", "motor neutrinos disease", "motor neutrino disease"

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: (((("motor neurone disease") OR ("motor neuron disease"))) OR ((("motor neurons disease") OR ("motor neutrons disease"))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"motor neurone disease\") or (\"motor neuron disease\"))) or (((\"motor neurons disease\") OR (\"motor neutrons disease\"))))~".
• Removing quotes may allow a broader search: (((( motor neurone disease ) or ( motor neuron disease ))) or ((( motor neurons disease ) OR ( motor neutrons disease ))))~.
• Adding a wildcard symbol may retrieve word variants: (((("motor neurone disease") or ("motor neuron disease"))) or ((("motor neurons disease") OR ("motor neutrons disease"))))*.