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