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