String sentencia =
            "%'"+"SELECT *n"    +"FROM alumnosn"+
            "WHERE dni LIKE '%"+filtrar+"%'"+
            "OR apyn LIKE '%"+filtrar+"%'"+
            " OR sexo LIKE '%"+filtrar+"%'" +
            " OR fec_nac LIKE '%"+filtrar+"%'"+
            " OR cant_mat_aprob LIKE '%"+filtrar+"%'"+
            " OR promedio LIKE '%"+filtrar+"%'"+
            " OR fec_ing LIKE '%"+filtrar+"%'"+
            " OR carrera LIKE '%"+filtrar+"%"+
            " AND estado LIKE '%"+estado+"%'";