Perhaps you should try some spelling variations:
"process control estadisticas methods." » "process control estadistica methods.", "process control estadistico methods.", "process control statistical methods.", "process control estadisticas metodos.", "process control estadisticas datos.", "process control estadisticas medicas."
"proces contre statistical methods." » "proces control statistical methods.", "proceso contra statistical methods.", "proces contreles statistical methods.", "voces contra statistical methods."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("proces contre statistical methods.") or ("process control estadisticas methods."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("proces contre statistical methods.") OR ("process control estadisticas methods."))*.
• Removing quotes may allow a broader search: (( proces contre statistical methods. ) or ( process control estadisticas methods. ))*.