Can Drupal's search module search for a substring? (Partial Search)

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-开发者_C百科results?

Maybe there is a plugin that does that?

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.

Recently I made a patch for Drupal's core search module to provide it with partial search (aka n-gram searches) ability. This is tested against Drupal 6.15 & 6.16 releases. You might want to read about patching.

On the other hand you can make use of Apache Solr Search Integration, Search Lucene API modules or other 3rd-party search solutions which takes more time to implement.

PorterStemmer module has its own different story in which you might be interested, too.

Yes. Fuzzy Search (module) does it. https://drupal.org/project/fuzzysearch

Drupal Finder does it somehow, namely: it has an autosuggest feature, so if You start typich sand it should suggest You a node containing sandwich.