Talvez deva tentar algumas variações de ortografia:
airways comparison » airway comparison (Expandir a Pesquisa), pathways comparison (Expandir a Pesquisa), assays comparison (Expandir a Pesquisa)
comparison law » comparison low (Expandir a Pesquisa), comparison land (Expandir a Pesquisa), comparison a (Expandir a Pesquisa)
rat compare » rat compared (Expandir a Pesquisa), rate compare (Expandir a Pesquisa), rats compare (Expandir a Pesquisa)
nat2 comp » nat2 com (Expandir a Pesquisa), aav2 comp (Expandir a Pesquisa)
a airways » _ airways (Expandir a Pesquisa), a airway (Expandir a Pesquisa), rat airways (Expandir a Pesquisa)
compare a » compare _ (Expandir a Pesquisa)
comp can » camp can (Expandir a Pesquisa), chimp can (Expandir a Pesquisa), clamp can (Expandir a Pesquisa)
law netw » law new (Expandir a Pesquisa), law note (Expandir a Pesquisa), law need (Expandir a Pesquisa)
can now » can new (Expandir a Pesquisa), can non (Expandir a Pesquisa), can ngoc (Expandir a Pesquisa)
a rat » _ rat (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: (( 2 nat2 comp can now ) or ((( a airways comparison law netw ) or ( a rat compare a new ))))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (( 2 nat2 comp can now ) OR ((( a airways comparison law netw ) OR ( a rat compare a new )))).
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( 2 nat2 comp can now ) or ((( a airways comparison law netw ) or ( a rat compare a new ))))*.