Perhaps you should try some spelling variations:
substring searching » sorting searching, abstracting searching
information agents » information age, information access, information about
fourth dimension » four dimensions, fifth dimension, fourth session
string searching » sorting searching, string matching, making searching
agents fourth » twenty fourth, axes fourth, agents folate

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

• Performing a fuzzy search may retrieve terms with similar spellings: information agents fourth dimension ((string searching) or (substring searching))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: information agents fourth dimension ((string searching) OR (substring searching)).
• Adding a wildcard symbol may retrieve word variants: information agents fourth dimension ((string searching) or (substring searching))*.