Talvez deva tentar algumas variações de ortografia:
decrease observed » decay observed (Expandir a busca), case observed (Expandir a busca)
observed objects » observed effects (Expandir a busca), submerged objects (Expandir a busca), buried objects (Expandir a busca)
decrease and » decreases and (Expandir a busca), decrease in (Expandir a busca), decrease of (Expandir a busca)
and decrease » and decreases (Expandir a busca), and decreased (Expandir a busca), and increase (Expandir a busca)
decrease to » decreased to (Expandir a busca), decrease toc (Expandir a busca), decrease the (Expandir a busca)

Você pode obter mais resultados ajustando o argumento de busca.

• Remover as aspas pode possibilitar buscas mais amplas: (( decrease to decrease and decrease ) OR ( decrease NOT decrease observed objects ))~.