Talvez deva tentar algumas variações de ortografia:
levels other » levels another (Expandir a Pesquisa), levels rather (Expandir a Pesquisa), levels over (Expandir a Pesquisa)
noise levels » noise level (Expandir a Pesquisa)
doses level » dose level (Expandir a Pesquisa), does level (Expandir a Pesquisa), dose levels (Expandir a Pesquisa)
doses liver » does liver (Expandir a Pesquisa), dose liver (Expandir a Pesquisa), dose live (Expandir a Pesquisa)
drug doses » drug dose (Expandir a Pesquisa), drug disease (Expandir a Pesquisa)
level ther » level theory (Expandir a Pesquisa), level rather (Expandir a Pesquisa), level three (Expandir a Pesquisa)
liver ther » liver other (Expandir a Pesquisa), live rather (Expandir a Pesquisa), liver thle2 (Expandir a Pesquisa)
drug noise » drug naive (Expandir a Pesquisa), drug nurse (Expandir a Pesquisa), during noise (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 doses level ther ) OR ((( drug doses liver ther ) OR ( drug noise levels other ))))~.
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( drug doses level ther ) or ((( drug doses liver ther ) or ( drug noise levels other ))))*.