Talvez deva tentar algumas variações de ortografia:
spinal nerve » retinal nerve (Expandir a Pesquisa)
nerve system » nervous system (Expandir a Pesquisa), drive system (Expandir a Pesquisa)
delta nerve » beta nerve (Expandir a Pesquisa), deltoid nerve (Expandir a Pesquisa), deltas served (Expandir a Pesquisa)
cenp nerve » deep nerve (Expandir a Pesquisa), cgrp nerve (Expandir a Pesquisa), dcnp nerve (Expandir a Pesquisa)
system dis » system dias (Expandir a Pesquisa), system dcs (Expandir a Pesquisa), system di (Expandir a Pesquisa)
nerve cat » nerve can (Expandir a Pesquisa), nerve case (Expandir a Pesquisa), nerve a (Expandir a Pesquisa)
i spinal » _ spinal (Expandir a Pesquisa), a spinal (Expandir a Pesquisa), i spiral (Expandir a Pesquisa)
j delta » j della (Expandir a Pesquisa), j delton (Expandir a Pesquisa)
cat dis » cat did (Expandir a Pesquisa), cat diets (Expandir a Pesquisa), cat diet (Expandir a Pesquisa)
a cenp » _ cenp (Expandir a Pesquisa), a cena (Expandir a Pesquisa)

You can also try:

• Europeana
• Digital Public Library of America
• CORE

Pode obter mais resultados ajustando a pesquisa.

• "As palabras AND, OR e NOT podem gerar pesquisas incorrectas; tente utilizar aspas": "(((( a cenp nerve system dis ) OR ( i spinal nerve system der ))) OR ( j delta nerve cat dis ))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( a cenp nerve system dis ) OR ( i spinal nerve system der ))) OR ( j delta nerve cat dis ))*.