Talvez deva tentar algumas variações de ortografia:
research systems » research synthesis (Expandir a Pesquisa)
mehta research » meta research (Expandir a Pesquisa), beta research (Expandir a Pesquisa), eha research (Expandir a Pesquisa)
recent nerve » prevent nerve (Expandir a Pesquisa), rodent nerve (Expandir a Pesquisa), recurrent nerve (Expandir a Pesquisa)
center nerve » cancer nerve (Expandir a Pesquisa), center nurse (Expandir a Pesquisa), letter nerve (Expandir a Pesquisa)
systems de » systems do (Expandir a Pesquisa), systems mems (Expandir a Pesquisa), systems data (Expandir a Pesquisa)
nerve vas » nerve a (Expandir a Pesquisa), nerve vi (Expandir a Pesquisa), nerve vii (Expandir a Pesquisa)
j center » j centner (Expandir a Pesquisa), j centeno (Expandir a Pesquisa), j cestero (Expandir a Pesquisa)
i recent » ii recent (Expandir a Pesquisa), 1 recent (Expandir a Pesquisa), iii recent (Expandir a Pesquisa)
vas dis » vas dias (Expandir a Pesquisa), vasc dis (Expandir a Pesquisa)
nerve c » nerve cn (Expandir a Pesquisa), nerve _ (Expandir a Pesquisa), nerve a (Expandir a Pesquisa)
c dos » e dos (Expandir a Pesquisa), a 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 center nerve vas dis ) OR ( i recent nerve c dos ))) OR ( a mehta research systems de ))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( j center nerve vas dis ) OR ( i recent nerve c dos ))) OR ( a mehta research systems de ))*.