Perhaps you should try some spelling variations:
"process control estadisticas methods." » "process control estadisticas metodos.", "process control estadisticas datos.", "process control estadisticas medicas.", "process control estadistica methods.", "process control estadistico methods.", "process control statistical methods."
"procesos health statistical methods." » "proceso health statistical methods.", "procesos health statistics methods."

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

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