Talvez deva tentar algumas variações de ortografia:
native levels » native livers (Expandir a Pesquisa), relative levels (Expandir a Pesquisa), fatigue levels (Expandir a Pesquisa)
levels other » levels another (Expandir a Pesquisa), levels rather (Expandir a Pesquisa), levels over (Expandir a Pesquisa)
mouse sleep » mouse spleen (Expandir a Pesquisa)
sleep where » sleep when (Expandir a Pesquisa), sleep while (Expandir a Pesquisa), asleep while (Expandir a Pesquisa)
drug native » drug naive (Expandir a Pesquisa), drug nativa (Expandir a Pesquisa), drug negative (Expandir a Pesquisa)
drug mouse » drug house (Expandir a Pesquisa), drug misuse (Expandir a Pesquisa), drug houses (Expandir a Pesquisa)
drugs does » drugs do (Expandir a Pesquisa)
does liver » does life (Expandir a Pesquisa), does laser (Expandir a Pesquisa), drives liver (Expandir a Pesquisa)
liver ther » liver other (Expandir a Pesquisa), liver rather (Expandir a Pesquisa), live rather (Expandir a Pesquisa)

You can also try:

• Europeana
• Digital Public Library of America
• CORE

Pode obter mais resultados ajustando a pesquisa.

• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (( drug mouse sleep where ) OR ((( drugs does liver ther ) OR ( drug native levels other ))))~.
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( drug mouse sleep where ) or ((( drugs does liver ther ) or ( drug native levels other ))))*.