Perhaps you should try some spelling variations:
introduction comparative » production comparative, introduction corporate, introduction cognitive
programming errors » programming effort, programming reactors, programming entropy
programming perl » programming pearls, programming part, programming paul
concept care » concepts care, concept car, concept card

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

• Performing a fuzzy search may retrieve terms with similar spellings: introduction comparative ((programming errors) or (programming perl)) concept care~.
• If you are trying to use Boolean operators, they must be ALL CAPS: introduction comparative ((programming errors) OR (programming perl)) concept care.
• Adding a wildcard symbol may retrieve word variants: introduction comparative ((programming errors) or (programming perl)) concept care*.