Talvez deva tentar algumas variações de ortografia:
levels rather » level rather (Expandir a Pesquisa), cells rather (Expandir a Pesquisa)
dose levels » noise levels (Expandir a Pesquisa)
nurse level » nurses level (Expandir a Pesquisa), nursery level (Expandir a Pesquisa), nurses levels (Expandir a Pesquisa)
level three » level tree (Expandir a Pesquisa), novel three (Expandir a Pesquisa), label three (Expandir a Pesquisa)
drugs does » drugs do (Expandir a Pesquisa)
does liver » does life (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)
drug nurse » drug nurses (Expandir a Pesquisa), drug burst (Expandir a Pesquisa), drug noise (Expandir a Pesquisa)
drug dose » drug dosage (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 dose levels rather ) OR ((( drugs does liver ther ) OR ( drug nurse level three ))))~.
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( drug dose levels rather ) or ((( drugs does liver ther ) or ( drug nurse level three ))))*.