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 estadisticas methods." » "process control estadistica methods.", "process control estadistico methods.", "process control statistical methods.", "process control estadisticas metodos.", "process control estadisticas datos.", "process control estadisticas medicas."

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

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