Parsing a string into parts, only consecutive words, not a power set

I'm trying to write a search query to find articles from a database. I would like to take the search string the user enters and look for a specific set of possible search terms. If the user entered the search string "listing of average salaries in germany for 2011" I would like to generate a list of terms to hunt for. I figured I would look for the whole string and for partial strings of consecutive words. That is I want to search for "listing of average salaries" and "germany for 2011" but not "listing germany 2011".

So far I have this bit of code to generate my search terms:

  $searchString = "listing of average salaries in germany for 2011";
  $searchTokens = explode(" ", $searchString);
  $searchTerms = array($searchString);

  $tokenCount = count($searchTokens);
  for($max=$tokenCount - 1; $max>0; $max--) {
      $termA = "";
      $termB = "";
      for ($i=0; $i < $max; $i++) {
          $termA .= $searchTokens[$i] . " ";
          $termB .= $searchTokens[($tokenCount-$max) + $i] . " ";
      }
      array_push($searchTerms, $termA);
      array_push($searchTerms, $termB);
  }

  print_r($searchTerms);

and its giving me this list of terms:

listing of average salaries in germany for 2011
listing of average salaries in germany for
of average salaries in germany for 2011
listing of average salaries in germany
average salaries in germany for 2011
listing of average salaries in
salaries in germany for 2011
listing of average salaries
in germany for 2011
listing of average
germany for 2011
listing of
for 2011
listing
2011

What I'm not sure how to get are the missing terms:

of average salaries in germany for
of average salaries in germany
average salaries in germany for
of average salaries in
average salaries in germany
salaries in germany for
etc...

Update

I'm not looking for a "power set" so answers like this or this aren't valid. For example I do not want these in my list of terms:

average germany
listing salaries 2011
of germany for

I'm looking for consecutive words only.

Solution

You want to find all sequential subsets of the exploded string, just start at offset=0 and split the array with length=1 up to count-offset:

$search_string = 'listing of average salaries in germany for 2011';
$search_array = explode(' ',$search_string);
$count = count($search_array);

$s = array();
$min_length = 1;

for ($offset=0;$offset<$count;$offset++) {
    for ($length=$min_length;$length<=$count-$offset;$length++) {
        $match = array_slice($search_array,$offset,$length);
        $search_matches []= join(' ',$match);
    }
}

print_r($search_array);
print_r($search_matches);