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 estadistica methods." » "process control estadistico methods.", "process control statistical methods.", "process economia estadistica methods.", "process control estadisticas metodos.", "process control estadisticas medicas.", "procesos control estadistica methods.", "procesal control estadistica methods."

Try widening your search to All Fields.

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