Perhaps you should try some spelling variations:
"proceso control estadistico factor." » "proceso control estadistico con.", "process control estadistico factor.", "proceso contra estadistico factor.", "proceso contralos estadistico factor."
"procesos control statistical methods." » "process control statistical methods.", "proceso contra statistical methods.", "procesos contables statistical methods.", "procesos control statistics methods.", "procesos control estadisticas methods."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("procesos control statistical methods.") or ("proceso control estadistico factor."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("procesos control statistical methods.") OR ("proceso control estadistico factor.")).
• Removing quotes may allow a broader search: (( procesos control statistical methods. ) or ( proceso control estadistico factor. )).
• Adding a wildcard symbol may retrieve word variants: (("procesos control statistical methods.") or ("proceso control estadistico factor."))*.