Talvez deva tentar algumas variações de ortografia:
decrease periodontal » increased periodontal (Expandir a busca), disease periodontal (Expandir a busca), diseases periodontal (Expandir a busca)
periodontal defect » periodontal defects (Expandir a busca), periodontal desfecho (Expandir a busca), periodontal effects (Expandir a busca)
decrease the » decreases the (Expandir a busca), decrease in (Expandir a busca), decrease of (Expandir a busca)
the decrease » to decrease (Expandir a busca), and decrease (Expandir a busca)
decrease not » decrease of (Expandir a busca), decrease akt (Expandir a busca), decrease at (Expandir a busca)
not decrease » to decrease (Expandir a busca), not increase (Expandir a busca), and decrease (Expandir a busca)

Você pode obter mais resultados ajustando o argumento de busca.

• Caso esteja tentando utilizar os operadores booleanos, deve escrevê-los em Letras MAIÚSCULAS: (( decrease _ decrease the decrease ) OR ( decrease NOT decrease periodontal defect ))~.
• As palavras AND, OR e NOT pode ocasionar problemas na busca; tente utilizar as aspas: "(( decrease _ decrease the decrease ) OR ( decrease not decrease periodontal defect ))~".
• Adicionar um caractere curinga pode recuperar variações da palavra buscada: (( decrease _ decrease the decrease ) OR ( decrease not decrease periodontal defect ))*.