public IEnumerable<NGANH_SearchResult> NGANH_Search(NGANH_SearchResult data, int? top)
 {
     try
     {
         using (var db = new OOAD_EDUManagementDataContext())
         {
             return db.NGANH_Search(data.maNganh,
                                   data.maXNganh,
                                   data.maLoaiHinhDaoTao,
                                   data.tenNganh,
                                   data.maNguoiLap,
                                   data.thoiGianLap == null ? "" : data.thoiGianLap.Value.ToString(Constants.FormatDate),
                                   data.maNguoiDuyet,
                                   data.thoiGianDuyet == null ? "" : data.thoiGianDuyet.Value.ToString(Constants.FormatDate),
                                   data.maTrangThaiDuyet,
                                   data.trangThaiDuLieu,
                                   top).ToList();
         }
     }
     catch (Exception e) { return null; }
 }