Talvez deva tentar algumas variações de ortografia:
research systems » research synthesis (Expandir a Pesquisa)
mental research » dental research (Expandir a Pesquisa), central research (Expandir a Pesquisa), neonatal research (Expandir a Pesquisa)
cancer merece » cancer m.r.c (Expandir a Pesquisa), cancer march (Expandir a Pesquisa), cancer marine (Expandir a Pesquisa)
systems dis » systems disk (Expandir a Pesquisa), systems tdis (Expandir a Pesquisa), systems dss (Expandir a Pesquisa)
merece can » merece a (Expandir a Pesquisa), merece la (Expandir a Pesquisa), merve can (Expandir a Pesquisa)
cent nerve » bent nerve (Expandir a Pesquisa), recent nerve (Expandir a Pesquisa), crest nerve (Expandir a Pesquisa)
j cancer » j canter (Expandir a Pesquisa), j cantero (Expandir a Pesquisa), j candel (Expandir a Pesquisa)
j mental » j mengual (Expandir a Pesquisa), j mena (Expandir a Pesquisa), j mehta (Expandir a Pesquisa)
can dis » can disc (Expandir a Pesquisa), van dis (Expandir a Pesquisa), can die (Expandir a Pesquisa)
nerve a » nerve _ (Expandir a Pesquisa)
i cent » i cento (Expandir a Pesquisa), ai cent (Expandir a Pesquisa), ii cent (Expandir a Pesquisa)
a dis » a dos (Expandir a Pesquisa), a des (Expandir a Pesquisa), a dia (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 cancer merece can dis ) or ( i cent nerve a dis ))) or ( j mental research systems dis ))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (((( j cancer merece can dis ) OR ( i cent nerve a dis ))) OR ( j mental research systems dis )).
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( j cancer merece can dis ) or ( i cent nerve a dis ))) or ( j mental research systems dis ))*.