Perhaps you should try some spelling variations:
"comicas matematicas computer program." » "comicas mathematics computer program.", "comicas matematicas como program.", "comicas matematicas comics program.", "basicas matematicas computer program.", "ciencias matematicas computer program.", "logica matematica computer program.", "comicas matematicas computer programs."
"basicas matematica tomo programming." » "basicas matematicas tomo programming.", "fisica matematica tomo programming.", "logica matematica tomo programming.", "basicas matematica logic programming.", "basicas matematica web programming.", "basicas matematica java programming.", "basicas matematica como programming.", "basicas matematicas como 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: (("comicas matematicas computer program.") or ("basicas matematica tomo programming."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("comicas matematicas computer program.") OR ("basicas matematica tomo programming.")).
• Removing quotes may allow a broader search: (( comicas matematicas computer program. ) or ( basicas matematica tomo programming. )).
• Adding a wildcard symbol may retrieve word variants: (("comicas matematicas computer program.") or ("basicas matematica tomo programming."))*.