Perhaps you should try some spelling variations:
"proces control estadistico datos." » "proces control estadisticas datos.", "proces control estadistico factor.", "proces control estadistica casos.", "proces contre estadistico datos.", "proces contreles estadistico datos.", "proceso contra estadistico datos."
"process control statistical methods." » "procesos control statistical methods.", "proceso control statistical methods.", "procesal control statistical methods.", "process control statistics methods.", "process 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: (("process control statistical methods.") or ("proces control estadistico datos."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("process control statistical methods.") OR ("proces control estadistico datos.")).
• Removing quotes may allow a broader search: (( process control statistical methods. ) or ( proces control estadistico datos. )).
• Adding a wildcard symbol may retrieve word variants: (("process control statistical methods.") or ("proces control estadistico datos."))*.