Talvez deva tentar algumas variações de ortografia:
pcr compared » pcr combined (Expandir a Pesquisa)
compared can » compared case (Expandir a Pesquisa), compared a (Expandir a Pesquisa), compared law (Expandir a Pesquisa)
computer can » computers can (Expandir a Pesquisa), computer case (Expandir a Pesquisa), computer a (Expandir a Pesquisa)
hair comb » hair coat (Expandir a Pesquisa), hair coil (Expandir a Pesquisa), hair cord (Expandir a Pesquisa)
comb can » comb jean (Expandir a Pesquisa), comb n (Expandir a Pesquisa), comb a (Expandir a Pesquisa)
can ngoc » van ngoc (Expandir a Pesquisa), tran ngoc (Expandir a Pesquisa), phan ngoc (Expandir a Pesquisa)
j hair » j haig (Expandir a Pesquisa), j haar (Expandir a Pesquisa), j haidry (Expandir a Pesquisa)
al pcr » al par (Expandir a Pesquisa), sl pcr (Expandir a Pesquisa), tail pcr (Expandir a Pesquisa)
a ut » a gut (Expandir a Pesquisa), a cut (Expandir a Pesquisa), a nut (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": "(((( j hair comb can ngoc ) OR ( al pcr compared can ngoc ))) OR ( a ut computer can new ))~".
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (((( j hair comb can ngoc ) OR ( al pcr compared can ngoc ))) OR ( a ut computer can new ))*.