Perhaps you should try some spelling variations:
"investigacion logistica del servicio" » "investigacion holistica del servicio", "investigacion linguistica del servicio", "investigacion artistica del servicio", "investigacion logistica de servicio", "investigacion logistica en servicio", "investigacion logistico de 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 3 servicio"
"investigacion objetivo 2 servicio" » "investigacion objetivo de servicio", "investigacion objetivo 12 servicio", "investigacion objetivo 23 servicio", "investigacion objetivo 2 servicios"

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 objetivo 2 servicio"))) or ((("investigacion logistica 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 objetivo 2 servicio"))) OR ((("investigacion logistica del servicio") OR ("investigacion operativa del servicio")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"investigacion objetivo del servicio\") OR (\"investigacion objetivo 2 servicio\"))) or (((\"investigacion logistica del servicio\") or (\"investigacion operativa del servicio\"))))".
• Removing quotes may allow a broader search: (((( investigacion objetivo del servicio ) OR ( investigacion objetivo 2 servicio ))) or ((( investigacion logistica del servicio ) or ( investigacion operativa del servicio )))).
• Adding a wildcard symbol may retrieve word variants: (((("investigacion objetivo del servicio") OR ("investigacion objetivo 2 servicio"))) or ((("investigacion logistica del servicio") or ("investigacion operativa del servicio"))))*.