Talvez deva tentar algumas variações de ortografia:
central nerve » ventral nerve (Expandir a Pesquisa), central nervous (Expandir a Pesquisa), central neural (Expandir a Pesquisa)
survey system » surgery system (Expandir a Pesquisa), prey system (Expandir a Pesquisa), grey system (Expandir a Pesquisa)
bent nerve » absent nerve (Expandir a Pesquisa), mental nerve (Expandir a Pesquisa), dental 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)
system di » system de (Expandir a Pesquisa), system d (Expandir a Pesquisa), system dias (Expandir a Pesquisa)
case disc » cause disc (Expandir a Pesquisa), case di (Expandir a Pesquisa), case dose (Expandir a Pesquisa)
cat diet » cat diets (Expandir a Pesquisa), fat diet (Expandir a Pesquisa), eat diet (Expandir a Pesquisa)
j bent » j benet (Expandir a Pesquisa), j bento (Expandir a Pesquisa), j bena (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 survey system di ))) OR ( j bent nerve case disc ))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( i central nerve cat diet ) OR ( i current survey system di ))) OR ( j bent nerve case disc ))*.