Talvez deva tentar algumas variações de ortografia:
research system » research systems (Expandir a Pesquisa)
renal research » retinal research (Expandir a Pesquisa), legal research (Expandir a Pesquisa), regional research (Expandir a Pesquisa)
central nerve » ventral nerve (Expandir a Pesquisa), central nervous (Expandir a Pesquisa), central neural (Expandir a Pesquisa)
center have » centers have (Expandir a Pesquisa), centres have (Expandir a Pesquisa), cancer have (Expandir a Pesquisa)
i central » coli central (Expandir a Pesquisa), hemi central (Expandir a Pesquisa)
system di » system de (Expandir a Pesquisa), system d (Expandir a Pesquisa), system dias (Expandir a Pesquisa)
j center » j centner (Expandir a Pesquisa), 2 center (Expandir a Pesquisa), 19 center (Expandir a Pesquisa)
nerve c » nerve cn (Expandir a Pesquisa), nerve co (Expandir a Pesquisa), nerve ct (Expandir a Pesquisa)
j renal » j real (Expandir a Pesquisa), j renaldi (Expandir a Pesquisa), j renata (Expandir a Pesquisa)
have v » have _ (Expandir a Pesquisa), have a (Expandir a Pesquisa), have 3 (Expandir a Pesquisa)
v dis » v dias (Expandir a Pesquisa), v disc (Expandir a Pesquisa), _ dis (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.

• Performing a fuzzy search may retrieve terms with similar spellings: (((( j center have v dis ) or ( i central nerve c dis ))) or ( j renal research system di ))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (((( j center have v dis ) OR ( i central nerve c dis ))) OR ( j renal research system di )).
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( j center have v dis ) or ( i central nerve c dis ))) or ( j renal research system di ))*.