Perhaps you should try some spelling variations:
"proceso contralos statistical methods." » "proceso control statistical methods.", "proceso contra statistical methods.", "proces contreles statistical methods.", "procesos contables statistical methods."
"process control estadistico methods." » "process control statistical methods.", "process control estadisticas metodos.", "procesos control estadistico methods.", "procesal control estadistico methods."

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

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