Talvez deva tentar algumas variações de ortografia:
survey comparison » surgery comparison (Expandir a Pesquisa), survey comparing (Expandir a Pesquisa), survival comparison (Expandir a Pesquisa)
comparison low » comparison long (Expandir a Pesquisa), comparison do (Expandir a Pesquisa), comparison bot (Expandir a Pesquisa)
rat compared » rats compared (Expandir a Pesquisa), rate compared (Expandir a Pesquisa), fat compared (Expandir a Pesquisa)
compared a » compared _ (Expandir a Pesquisa)
j survey » a survey (Expandir a Pesquisa), 1 survey (Expandir a Pesquisa), 2 survey (Expandir a Pesquisa)
low now » low non (Expandir a Pesquisa), how now (Expandir a Pesquisa), law now (Expandir a Pesquisa)
2 natl » 2 nat2 (Expandir a Pesquisa), 2 nacl (Expandir a Pesquisa)
j rat » j rath (Expandir a Pesquisa), _ rat (Expandir a Pesquisa), a rat (Expandir a Pesquisa)
compr » comer (Expandir a Pesquisa)
ngoc » ngo (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 natl compr tran ngoc ) or ((( j survey comparison low now ) or ( j rat compared a new ))))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (( 2 natl compr tran ngoc ) OR ((( j survey comparison low now ) OR ( j rat compared a new )))).
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( 2 natl compr tran ngoc ) or ((( j survey comparison low now ) or ( j rat compared a new ))))*.