Perhaps you should try some spelling variations:
"procesos teoricas practices methods." » "procesos teoricos practicos methods.", "procesos teorico practicas methods.", "procesos teorico practicos methods.", "procesos teorias practices methods.", "procesos memorias practices methods.", "propuestas teoricas practices methods."
"process control statistical methods." » "proceso control statistical methods.", "procesal control statistical methods.", "process control statistics methods.", "process control estadisticas 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: (("process control statistical methods.") OR ("procesos teoricas practices methods."))~.
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