Search module in drupal 7
Look at the module  Fuzzy Search , this may solve your problem.


  This module provides drupal sites with a fuzzy search engine to allow
  for broader keyword matches including partial or misspelled keywords.
  
  Fuzzy matching is implemented by using ngrams. Each word in a node is
  split into 3 (default) letter lengths, so 'apple' gets indexed with 3
  smaller strings 'app', 'ppl', 'ple'. The effect of this is that as
  long as your search matches X percentage (administerable in the admin
  settings) of the word the node will be pulled up in the results.