// Fetch the ISYS engine from application scope
IISYSAsp isys = (IISYSAsp) Application["ISYS"];

// Open the required index
IISYSIndex index = (IISYSIndex) isys.OpenIndex(@"c:\index");

// Execute the search
IISYSResultList results = index.PerformFind("manager", 0);
try {
  // Sort the result list by relevance
  results.Sort(SortRelevance);

  // Truncate the result list to 1000 items
  results.Truncate(1000);

  // Save the result list to disk
  searchId = results.Save();
finally {
  System.Runtime.InteropServices.ReleaseComObject(results);
}