Perhaps you should try some spelling variations:
"economicos mathematics computer program." » "economicos matematicos computer program.", "economics mathematical computer program.", "economia matematica computer program.", "economicos mathematics computer programs."
"basicas matematicas como programming." » "comicas matematicas como programming.", "benditas matematicas como programming.", "fisica matematica como programming.", "basicas matematica como programming.", "basicas matematicas con programming.", "basicas matematica tomo programming.", "basicas matematicas control programming.", "basicas matematicas logic programming.", "basicas matematicas computer programming."

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: (("economicos mathematics computer program.") or ("basicas matematicas como programming."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("economicos mathematics computer program.") OR ("basicas matematicas como programming.")).
• Removing quotes may allow a broader search: (( economicos mathematics computer program. ) or ( basicas matematicas como programming. )).
• Adding a wildcard symbol may retrieve word variants: (("economicos mathematics computer program.") or ("basicas matematicas como programming."))*.