Talvez deva tentar algumas variações de ortografia:
central nerve » ventral nerve (Expandir a Pesquisa), central nervous (Expandir a Pesquisa), central neural (Expandir a Pesquisa)
current state » current status (Expandir a Pesquisa)
system dis » system dias (Expandir a Pesquisa), system dcs (Expandir a Pesquisa), system di (Expandir a Pesquisa)
bela nerve » beta nerve (Expandir a Pesquisa), pgla nerve (Expandir a Pesquisa), delays nerve (Expandir a Pesquisa)
i central » coli central (Expandir a Pesquisa), hemi central (Expandir a Pesquisa)
nerve cat » nerve can (Expandir a Pesquisa), nerve a (Expandir a Pesquisa), nerve c (Expandir a Pesquisa)
cat diet » cat diets (Expandir a Pesquisa), fat diet (Expandir a Pesquisa), eat diet (Expandir a Pesquisa)
case dis » case disc (Expandir a Pesquisa), case di (Expandir a Pesquisa), case does (Expandir a Pesquisa)
j bela » j bell (Expandir a Pesquisa), j belval (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": "(((( i central nerve cat diet ) OR ( i current state system dis ))) OR ( j bela nerve case dis ))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( i central nerve cat diet ) OR ( i current state system dis ))) OR ( j bela nerve case dis ))*.