Perhaps you should try some spelling variations:
"progresos tecnicos artisticas methods." » "progresos tecnicas artisticas methods.", "progresos tecnica artistica methods.", "progresos tecnicas estadisticas methods.", "progreso tecnico artisticas 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."

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 ("progresos tecnicos artisticas methods."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"proceso control statistical methods.\") OR (\"progresos tecnicos artisticas methods.\"))".
• Removing quotes may allow a broader search: (( proceso control statistical methods. ) OR ( progresos tecnicos artisticas methods. )).
• Adding a wildcard symbol may retrieve word variants: (("proceso control statistical methods.") OR ("progresos tecnicos artisticas methods."))*.