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."
"progresos tecnicos artisticas methods." » "progresos tecnicas artisticas methods.", "progresos tecnica artistica methods.", "progresos tecnicas estadisticas methods.", "progreso tecnico artisticas methods."

You may be able to get more results by adjusting your search query.

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