Perhaps you should try some spelling variations:
"investigacion linguistica del servicio" » "investigacion logistica del servicio", "investigacion diagnostica del servicio", "investigacion neurolinguistica del servicio", "investigacion linguistica de servicio", "investigacion linguistico de servicio", "investigacion linguistica en servicio"
"investigacion operativa del servicio" » "investigacion operacional del servicio", "investigacion educativa del servicio", "investigacion formativa del servicio", "investigacion operativa de servicio", "investigacion cooperativa de servicio"
"investigacion objetivo del servicio" » "investigacion objetivos del servicio", "investigacion objetivo de servicio", "investigacion objetivo 2 servicio"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("investigacion objetivo del servicio") or ((("investigacion linguistica del servicio") or ("investigacion operativa del servicio"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("investigacion objetivo del servicio") OR ((("investigacion linguistica del servicio") OR ("investigacion operativa del servicio")))).
• Removing quotes may allow a broader search: (( investigacion objetivo del servicio ) or ((( investigacion linguistica del servicio ) or ( investigacion operativa del servicio )))).
• Adding a wildcard symbol may retrieve word variants: (("investigacion objetivo del servicio") or ((("investigacion linguistica del servicio") or ("investigacion operativa del servicio"))))*.