Perhaps you should try some spelling variations:
"proceso sociales statistical methods." » "proceso sociology statistical methods.", "proceso sciences statistical methods.", "proceso science statistical methods.", "procesos sociales statistical methods.", "proceso social statistical methods.", "procesos locales statistical methods."
"process control estadisticas datos." » "process control estadistica datos.", "process control estadistico datos.", "process control statistical datos.", "process control estadistica casos.", "process control estadisticas metodos.", "process control estadisticas de."

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