Perhaps you should try some spelling variations:
"motor neuronal disease" » "motor neural disease", "motor neutronal disease", "motor neuroal disease"
"motor neurone disease" » "motor neutrone disease", "motor neuroe disease"
"motor neuron disease" » "motor neutron disease", "motor neuro disease"
"motor neurons disease" » "motor neutrons disease", "motor neuros disease"

You may be able to get more results by adjusting your search query.

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