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 card » concept car, concept art, concept based

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "introduction comparative ((programming errors) OR (programming perl)) concept card~".
• Adding a wildcard symbol may retrieve word variants: introduction comparative ((programming errors) OR (programming perl)) concept card*.