Talvez deva tentar algumas variações de ortografia:
active system » active systems (Expandir a Pesquisa), active systemic (Expandir a Pesquisa), reactive system (Expandir a Pesquisa)
absent active » absence active (Expandir a Pesquisa), absent native (Expandir a Pesquisa)
nerve system » nervous system (Expandir a Pesquisa), drive system (Expandir a Pesquisa)
benign nerve » benign nevi (Expandir a Pesquisa), benign neck (Expandir a Pesquisa), benign beale (Expandir a Pesquisa)
bent nerve » absent nerve (Expandir a Pesquisa), mental nerve (Expandir a Pesquisa), dental nerve (Expandir a Pesquisa)
system de » system der (Expandir a Pesquisa), system delay (Expandir a Pesquisa)
nerve cat » nerve can (Expandir a Pesquisa), nerve ct (Expandir a Pesquisa), nerve cut (Expandir a Pesquisa)
cat diets » fat diets (Expandir a Pesquisa), salt diets (Expandir a Pesquisa), cow diets (Expandir a Pesquisa)
_ absent » _ absence (Expandir a Pesquisa)

You can also try:

• Europeana
• Digital Public Library of America
• CORE

Pode obter mais resultados ajustando a pesquisa.

• Performing a fuzzy search may retrieve terms with similar spellings: (( a bent nerve system de ) or ((( _ absent active system de ) or ( _ benign nerve cat diets ))))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (( a bent nerve system de ) OR ((( _ absent active system de ) OR ( _ benign nerve cat diets )))).
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( a bent nerve system de ) or ((( _ absent active system de ) or ( _ benign nerve cat diets ))))*.