Perhaps you should try some spelling variations:
"los estados e investigaciones" » "los estados de investigaciones", "los estados e investigacion", "los estados las investigaciones", "los estado e investigaciones", "los estados y investigaciones", "loss estados e investigaciones"
"de estudios de investigations" » "de estudios fe investigations", "de estudios dike investigations", "de estudios de investigaciones", "de estudio de investigations"

Try widening your search to All Fields.

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: (("los estados e investigaciones") OR ("de estudios de investigations")).
• Removing quotes may allow a broader search: (( los estados e investigaciones ) or ( de estudios de investigations )).
• Adding a wildcard symbol may retrieve word variants: (("los estados e investigaciones") or ("de estudios de investigations"))*.