Talvez deva tentar algumas variações de ortografia:
dual roles » dual role (Expandir a Pesquisa)
roles con » roles en (Expandir a Pesquisa), roles do (Expandir a Pesquisa)
oil bomb » oil body (Expandir a Pesquisa)
role van » role can (Expandir a Pesquisa), role dans (Expandir a Pesquisa), role a (Expandir a Pesquisa)
van ngoc » tran ngoc (Expandir a Pesquisa), vu ngoc (Expandir a Pesquisa), bao ngoc (Expandir a Pesquisa)
con net » con nee (Expandir a Pesquisa), non net (Expandir a Pesquisa), upon net (Expandir a Pesquisa)
j dual » j duval (Expandir a Pesquisa), j duan (Expandir a Pesquisa), j dull (Expandir a Pesquisa)
bomb a » bomb _ (Expandir a Pesquisa), bomb 1 (Expandir a Pesquisa), bomb 2 (Expandir a Pesquisa)
5 oil » _ oil (Expandir a Pesquisa), 5 il (Expandir a Pesquisa), l oil (Expandir a Pesquisa)
3 nac » 3 nacl (Expandir a Pesquisa), a nac (Expandir a Pesquisa), α nac (Expandir a Pesquisa)
_ nac » _ nad (Expandir a Pesquisa), _ nab (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: (( j dual roles con net ) or ((( 5 oil bomb a new ) or ( ((3 nac) OR (_ nac)) role van ngoc ))))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (( j dual roles con net ) OR ((( 5 oil bomb a new ) OR ( ((3 nac) OR (_ nac)) role van ngoc ))))*.
• "As palabras AND, OR e NOT podem gerar pesquisas incorrectas; tente utilizar aspas": "(( j dual roles con net ) or ((( 5 oil bomb a new ) or ( ((3 nac) OR (_ nac)) role van ngoc ))))*".