Talvez deva tentar algumas variações de ortografia:
research systems » research synthesis (Expandir a Pesquisa)
meng research » among research (Expandir a Pesquisa), being research (Expandir a Pesquisa), lung research (Expandir a Pesquisa)
center nurse » center nurses (Expandir a Pesquisa), letter nurse (Expandir a Pesquisa), cancer nurse (Expandir a Pesquisa)
real nerve » renal nerve (Expandir a Pesquisa), reveal nerve (Expandir a Pesquisa), fetal nerve (Expandir a Pesquisa)
systems de » systems do (Expandir a Pesquisa), systems mems (Expandir a Pesquisa), systems data (Expandir a Pesquisa)
nurse cat » nurse can (Expandir a Pesquisa), nurse cadet (Expandir a Pesquisa), nurse can't (Expandir a Pesquisa)
j center » j centner (Expandir a Pesquisa), 2 center (Expandir a Pesquisa), 3 center (Expandir a Pesquisa)
cat dis » cat did (Expandir a Pesquisa), cat diets (Expandir a Pesquisa), cat diet (Expandir a Pesquisa)
nerve c » nerve cn (Expandir a Pesquisa), nerve _ (Expandir a Pesquisa), nerve a (Expandir a Pesquisa)
i real » i really (Expandir a Pesquisa)
c dias » c diaz (Expandir a Pesquisa)
j meng » j mena (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 nurse cat dis ) OR ( i real nerve c dias ))) OR ( j meng research systems de ))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( j center nurse cat dis ) OR ( i real nerve c dias ))) OR ( j meng research systems de ))*.