Perhaps you should try some spelling variations:
"proceso control estadistico methods." » "proceso control estadisticas metodos.", "process control estadistico methods.", "proceso contra estadistico methods.", "proceso contralos estadistico methods."
"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: (("proceso control estadistico methods.") or ("procesos control statistical methods."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("proceso control estadistico methods.") OR ("procesos control statistical methods."))*.
• Removing quotes may allow a broader search: (( proceso control estadistico methods. ) or ( procesos control statistical methods. ))*.