Talvez deva tentar algumas variações de ortografia:
mental research » dental research (Expandir a Pesquisa), central research (Expandir a Pesquisa), neonatal research (Expandir a Pesquisa)
research system » research systems (Expandir a Pesquisa)
benign nerve » benign nevi (Expandir a Pesquisa), benign neck (Expandir a Pesquisa), benign beale (Expandir a Pesquisa)
mental nerve » ventral nerve (Expandir a Pesquisa), central nerve (Expandir a Pesquisa)
system dias » system dan (Expandir a Pesquisa), system dcs (Expandir a Pesquisa), system dcus (Expandir a Pesquisa)
nerve cat » nerve can (Expandir a Pesquisa), nerve case (Expandir a Pesquisa), nerve a (Expandir a Pesquisa)
j benign » j benigno (Expandir a Pesquisa), i benign (Expandir a Pesquisa), j benito (Expandir a Pesquisa)
i mental » vi mental (Expandir a Pesquisa), ii mental (Expandir a Pesquisa), i metal (Expandir a Pesquisa)
j mental » j mengual (Expandir a Pesquisa), j mena (Expandir a Pesquisa), j mehta (Expandir a Pesquisa)
cat die » cat diet (Expandir a Pesquisa), wat die (Expandir a Pesquisa), cat due (Expandir a Pesquisa)
nerve c » nerve cn (Expandir a Pesquisa), nerve _ (Expandir a Pesquisa), nerve a (Expandir a Pesquisa)
c dis » c dias (Expandir a Pesquisa), c disc (Expandir a Pesquisa), c dos (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": "(((( j benign nerve cat die ) OR ( i mental nerve c dis ))) OR ( j mental research system dias ))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( j benign nerve cat die ) OR ( i mental nerve c dis ))) OR ( j mental research system dias ))*.