Talvez deva tentar algumas variações de ortografia:
current surveys » current survey (Expandir a Pesquisa)
surveys system » survey system (Expandir a Pesquisa), survey systems (Expandir a Pesquisa), surveying system (Expandir a Pesquisa)
bent serve » best serve (Expandir a Pesquisa), bent nerve (Expandir a Pesquisa), stent serve (Expandir a Pesquisa)
serve fast » serve fts (Expandir a Pesquisa), service fasd (Expandir a Pesquisa)
system dcs » system dcus (Expandir a Pesquisa), system sdcs (Expandir a Pesquisa), system des (Expandir a Pesquisa)
beth serve » both serve (Expandir a Pesquisa), better serve (Expandir a Pesquisa), death serves (Expandir a Pesquisa)
serve case » nerve case (Expandir a Pesquisa), service case (Expandir a Pesquisa), reserve case (Expandir a Pesquisa)
fast diet » fast die (Expandir a Pesquisa), past diet (Expandir a Pesquisa), fast direct (Expandir a Pesquisa)
case does » cases does (Expandir a Pesquisa), cause does (Expandir a Pesquisa), base does (Expandir a Pesquisa)
i bent » i benth (Expandir a Pesquisa), i benet (Expandir a Pesquisa), i bento (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": "(((( i bent serve fast diet ) OR ( i current surveys system dcs ))) OR ( j beth serve case does ))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( i bent serve fast diet ) OR ( i current surveys system dcs ))) OR ( j beth serve case does ))*.