Talvez deva tentar algumas variações de ortografia:
based comparison » head comparison (Expandir a Pesquisa)
comparison can » comparisons can (Expandir a Pesquisa), comparison cam (Expandir a Pesquisa), comparison case (Expandir a Pesquisa)
comas caused » coma caused (Expandir a Pesquisa), cosmos caused (Expandir a Pesquisa), costs caused (Expandir a Pesquisa)
caused fetal » causes fetal (Expandir a Pesquisa), caused fatal (Expandir a Pesquisa), cause fetal (Expandir a Pesquisa)
combined a » combined ab (Expandir a Pesquisa), combined acl (Expandir a Pesquisa), combined afm (Expandir a Pesquisa)
l comas » l comps (Expandir a Pesquisa), l comeau (Expandir a Pesquisa)
a norte » a north (Expandir a Pesquisa)
_ based » _ base (Expandir a Pesquisa), _ bases (Expandir a Pesquisa)
c pcr » dc pcr (Expandir a Pesquisa), mc pcr (Expandir a Pesquisa), 3c pcr (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 l comas caused fetal ) or ((( c pcr combined a norte ) or ( _ based comparison can new ))))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (( j l comas caused fetal ) OR ((( c pcr combined a norte ) OR ( _ based comparison can new )))).
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( j l comas caused fetal ) or ((( c pcr combined a norte ) or ( _ based comparison can new ))))*.