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