Perhaps you should try some spelling variations:
la contaminacion » la contratacion (Expand Search), la conciliacion (Expand Search), la consolidacion (Expand Search)
control interno » control externo (Expand Search), controle externo (Expand Search)
prevencion del » prevencion de (Expand Search), prevencion y (Expand Search)
prevencion el » prevencion en (Expand Search), prevencion e (Expand Search), prevencion de (Expand Search)
integrados de » integrado de (Expand Search), integradora de (Expand Search), integrada de (Expand Search)
interno de » internos de (Expand Search), interna de (Expand Search), interno e (Expand Search)

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: (("((prevencion el) OR (prevencion del)) control integrados de la contaminacion") OR ("((prevencion el) OR (prevencion del)) control interno de la contaminacion"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"((prevencion el) OR (prevencion del)) control integrados de la contaminacion\") OR (\"((prevencion el) OR (prevencion del)) control interno de la contaminacion\"))".
• Removing quotes may allow a broader search: (( ((prevencion el) OR (prevencion del)) control integrados de la contaminacion ) OR ( ((prevencion el) OR (prevencion del)) control interno de la contaminacion )).
• Adding a wildcard symbol may retrieve word variants: (("((prevencion el) OR (prevencion del)) control integrados de la contaminacion") OR ("((prevencion el) OR (prevencion del)) control interno de la contaminacion"))*.