Talvez deva tentar algumas variações de ortografia:
disease develop » disease develops (Expandir a Pesquisa), disease developed (Expandir a Pesquisa), disease developing (Expandir a Pesquisa)
level theory » legal theory (Expandir a Pesquisa), model theory (Expandir a Pesquisa), cell theory (Expandir a Pesquisa)
drug disease » drug release (Expandir a Pesquisa)
develop them » develop type (Expandir a Pesquisa), develop age (Expandir a Pesquisa)
drugs does » drugs do (Expandir a Pesquisa)
does diet » does deep (Expandir a Pesquisa), does dietary (Expandir a Pesquisa)
diet ther » diets other (Expandir a Pesquisa), diet than (Expandir a Pesquisa), diet therapy (Expandir a Pesquisa)
de level » de leval (Expandir a Pesquisa), de leve (Expandir a Pesquisa), de leves (Expandir a Pesquisa)
drug de » drug dose (Expandir a Pesquisa), drug dna (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: (((( drugs does diet ther ) or ( drug de level theory ))) or ( drug disease develop them ))~.
• Se usar operadores Booleanos, por favor insira-os com letras MAIÚSCULAS: (((( drugs does diet ther ) OR ( drug de level theory ))) OR ( drug disease develop them ))*.