Talvez deva tentar algumas variações de ortografia:
norway comparison » airway comparison (Expandir a Pesquisa), way comparison (Expandir a Pesquisa), germany comparison (Expandir a Pesquisa)
rats compared » rates compared (Expandir a Pesquisa)
comparison a » comparison _ (Expandir a Pesquisa), comparison among (Expandir a Pesquisa), comparison based (Expandir a Pesquisa)
compared a » compared _ (Expandir a Pesquisa)
nat2 come » nat2 com (Expandir a Pesquisa)
come than » home than (Expandir a Pesquisa), time than (Expandir a Pesquisa), some thai (Expandir a Pesquisa)
j norway » _ norway (Expandir a Pesquisa), a norway (Expandir a Pesquisa), 1 norway (Expandir a Pesquisa)
j rats » j rath (Expandir a Pesquisa), j raes (Expandir a Pesquisa), rij rats (Expandir a Pesquisa)
a net » _ net (Expandir a Pesquisa), u net (Expandir a Pesquisa), a neo (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": "(( 2 nat2 come than non ) OR ((( j norway comparison a net ) OR ( j rats compared a new ))))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( 2 nat2 come than non ) OR ((( j norway comparison a net ) OR ( j rats compared a new ))))*.