Perhaps you should try some spelling variations:
"problemas contextos linguistics methodology." » "problemas contextos linguisticos methodology.", "problemas contexto linguistico methodology.", "problemas contacto linguistico methodology.", "problemas concretos linguistics methodology.", "problemas candentes linguistics methodology.", "problemas internos linguistics methodology."
"process control statistical methods." » "procesos 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 ("problemas contextos linguistics methodology."))~.
• Removing quotes may allow a broader search: (( process control statistical methods. ) or ( problemas contextos linguistics methodology. ))~.
• Adding a wildcard symbol may retrieve word variants: (("process control statistical methods.") or ("problemas contextos linguistics methodology."))*.