Talvez deva tentar algumas variações de ortografia:
negative rather » negative rate (Expandir a Pesquisa), negative rates (Expandir a Pesquisa), negative mother (Expandir a Pesquisa)
less negative » stress negative (Expandir a Pesquisa), its negative (Expandir a Pesquisa), has negative (Expandir a Pesquisa)
does develop » boys develop (Expandir a Pesquisa), loss develop (Expandir a Pesquisa), res develop (Expandir a Pesquisa)
develop them » develop type (Expandir a Pesquisa), develop age (Expandir a Pesquisa)
noise level » noise levels (Expandir a Pesquisa)
drug noise » drug naive (Expandir a Pesquisa), drug nurse (Expandir a Pesquisa), during noise (Expandir a Pesquisa)
level ther » level theory (Expandir a Pesquisa), level rather (Expandir a Pesquisa), levels other (Expandir a Pesquisa)
drug does » drug doses (Expandir a Pesquisa), drugs does (Expandir a Pesquisa), drug dose (Expandir a Pesquisa)
drug less » drugs less (Expandir a Pesquisa), drug loss (Expandir a Pesquisa), drug leads (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: (( drug does develop them ) or ((( drug less negative rather ) or ( drug noise level ther ))))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (( drug does develop them ) OR ((( drug less negative rather ) OR ( drug noise level ther )))).
• Se adicionar um carácter universal pode recuperar variações da palavra pesquisada: (( drug does develop them ) or ((( drug less negative rather ) or ( drug noise level ther ))))*.