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)
centeno nerve » central nerve (Expandir a Pesquisa), centeno jorge (Expandir a Pesquisa), centeno leyva (Expandir a Pesquisa)
recent nerve » prevent nerve (Expandir a Pesquisa), rodent nerve (Expandir a Pesquisa), recurrent nerve (Expandir a Pesquisa)
systems mem » systems mems (Expandir a Pesquisa), systems med (Expandir a Pesquisa), systems moems (Expandir a Pesquisa)
j centeno » a centeno (Expandir a Pesquisa), d centeno (Expandir a Pesquisa), j.a centeno (Expandir a Pesquisa)
nerve can » nerve canal (Expandir a Pesquisa), nerve case (Expandir a Pesquisa), nerve a (Expandir a Pesquisa)
i recent » ii recent (Expandir a Pesquisa), 1 recent (Expandir a Pesquisa), iii recent (Expandir a Pesquisa)
can dis » can disc (Expandir a Pesquisa), van dis (Expandir a Pesquisa), can die (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 centeno nerve can dis ) OR ( i recent nerve c dos ))) OR ( a mehta research systems mem ))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( j centeno nerve can dis ) OR ( i recent nerve c dos ))) OR ( a mehta research systems mem ))*.