青海省主要年份公路桥梁（1990-2004）

该数据集记录了青海省主要年份公路桥梁的统计数据，数据是按行年份划分的，按照孔径和使用年限分组。数据整理自青海省统计局发布的青海省统计年鉴。数据集包含1个数据表，为：主要年份公路桥梁1990-2004年.xls。其中2004年特大桥按国家规定的标准重新进行了划分数据。1990-2004年的数据表共有6个字段，分别为： 字段1：特大桥 字段2：大桥 字段3：中桥 字段4：小桥 字段5：隧道 字段6：永久式 字段7：公路隧道This dataset records statistical data on highway bridges in Qinghai Province for key years, with the data arranged by year and grouped by aperture and service life. The data was compiled from the Qinghai Statistical Yearbook published by the Qinghai Provincial Bureau of Statistics. The dataset contains one data table named "主要年份公路桥梁1990-2004年.xls". The data for mega bridges in 2004 was reclassified in accordance with national standard requirements. The data table from 1990 to 2004 has a total of 6 fields, which are listed as follows: Field 1: Mega Bridges Field 2: Large Bridges Field 3: Medium Bridges Field 4: Small Bridges Field 5: Tunnels Field 6: Permanent-type Structures Field 7: Highway Tunnels