Talvez deva tentar algumas variações de ortografia:
center serum » cancer serum (Expandir a Pesquisa), letter serum (Expandir a Pesquisa), better serum (Expandir a Pesquisa)
benzo serena » benz verena (Expandir a Pesquisa), bono serena (Expandir a Pesquisa), enzo sereni (Expandir a Pesquisa)
serum cause » serum causes (Expandir a Pesquisa), serum case (Expandir a Pesquisa), serum caspase (Expandir a Pesquisa)
senal nerve » renal nerve (Expandir a Pesquisa), senal merve (Expandir a Pesquisa), spinal nerve (Expandir a Pesquisa)
serena case » serena claire (Expandir a Pesquisa), serena kaiser (Expandir a Pesquisa), serena chile (Expandir a Pesquisa)
cause des » cause de (Expandir a Pesquisa), cause dna (Expandir a Pesquisa)
nerve can » merve can (Expandir a Pesquisa), nerve cat (Expandir a Pesquisa), nerve cn (Expandir a Pesquisa)
a center » a century (Expandir a Pesquisa)
i senal » i sena (Expandir a Pesquisa), i segnali (Expandir a Pesquisa), i seminal (Expandir a Pesquisa)
can dcs » can tdcs (Expandir a Pesquisa), can dce (Expandir a Pesquisa), can dags (Expandir a Pesquisa)
j benzo » j bento (Expandir a Pesquisa), j benito (Expandir a Pesquisa), j benton (Expandir a Pesquisa)
case di » case dti (Expandir a Pesquisa), case d (Expandir a Pesquisa), case de (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: (((( a center serum cause des ) or ( i senal nerve can dcs ))) or ( j benzo serena case di ))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (((( a center serum cause des ) OR ( i senal nerve can dcs ))) OR ( j benzo serena case di ))*.