Perhaps you should try some spelling variations:
communications convention » communications connections, communication connection, communication conversation
convention david » conversion david, conversation david, prevention david
parsons basic » person basic, parsing basics, parts basic
pearson basic » person basic, pearson barrie, pearson david

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

• Performing a fuzzy search may retrieve terms with similar spellings: communications convention david ((parsons basic) OR (pearson basic)) linear~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "communications convention david ((parsons basic) OR (pearson basic)) linear".
• Adding a wildcard symbol may retrieve word variants: communications convention david ((parsons basic) OR (pearson basic)) linear*.