1. A method of retrieving search results according to priorities from a plurality of database servers, using parallel computation performed by a plurality of said servers for a common query, the method comprises: i. receiving by a database server one or more search criteria related to a query, ii. searching by said database server search results from a locally associated database according to a predetermined search process for said search criteria related to the query, iii. associating by said database server priority discrimination levels with said search results, wherein priority discrimination levels are common to said plurality of database servers, and wherein a priority discrimination level refers to one or more search criteria that discriminate one or more search results from other search results, and wherein more restricting criteria are associated with higher priority discrimination levels, iv. transmitting by said database server for each priority discrimination level associated with search results, a signal in a respective communication slot assigned to a priority discrimination level for which the database server associates one or more search results in stage (iii), v. identifying by said database server indication on valid priority discrimination levels, wherein valid priority discrimination levels are detected by a detector that detects transmission performed within stage (iv) in different communication slots, and wherein transmission in a communication slot which is assigned to a priority discrimination level is indicative on a valid priority discrimination level, vi. transmitting by said database server search results associated with valid priority discrimination level according to priority determined by valid priority discrimination levels identified in stage (v).