Drupal\'s core search module, only searches for keywords, e.g. \"sandwich\". Can I make it search with a substring e.g. \"sandw\" and return my sandwich-results?
The most direct module for it is probably Fuzzy Search. I have not tried it. If you have more advanced search needs on a small to medium sized site, Search Lucene API is a fine solution. For a larger site, or truly advanced needs, Solr is the premiere solution.