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