Fuzzy search?

I once wrote a thesis on this; I got that it is best to compare the Russian words along the length of the maximal common prefix (as a percentage of the lesser of the length of words should be above threshold). Comparisons — do you compare words in pairs of rows, and output function of the similarity using the distance between the similar words.

try the Levenshtein distance schitat:http://ru.wikipedia.org/wiki/%D0%A0%D0%B0%D1%81%D1%81%D1%82%D0%BE%D1%8F%D0%BD%D0%B8%D0%B5_%D0%9B%D0%B5%D0%B2%D0%B5%D0%BD%D1%88%D1%82%D0%B5%D0%B9%D0%BD%D0%B0
example
\rbytes.com/topic/python/answers/580959-fuzzy-string-comparison

if(longStr.Contains(shortStr))

There are many different distances between the words, I would break the phrase into words and would have taken the average of the maximum obtained measures of pairwise matching words.

You can compare the method of trigrams. Will give a certain result, even if the words with different endings, etc.

Traditionally the Levenshtein distance.
\r
But I would recommend ispolzvat longest common subsequence. Thus, it is possible to introduce some penalty for the gaps between words.