Talvez deva tentar algumas variações de ortografia:
diffraction retention » filtration retention (Expandir a busca), diffraction criterion (Expandir a busca), attraction retention (Expandir a busca)
retention decrease » retention screws (Expandir a busca)
code diffraction » powder diffraction (Expandir a busca), wedge diffraction (Expandir a busca), wave diffraction (Expandir a busca)
python python » pythons python (Expandir a busca), piton python (Expandir a busca), pitons python (Expandir a busca)
code code » code cdc (Expandir a busca)

Você pode obter mais resultados ajustando o argumento de busca.

• Remover as aspas pode possibilitar buscas mais amplas: (( code code diffraction retention decrease ) OR ( _ python python python programming ))~.