Follow below steps to export a site, list, or document library by 
using Central Administration
- In Central Administration, on the Home page > Backup and Restore.
 - On the Backup and Restore page > Granular Backup > click Export a site or list.
 - On the Site or List Export page,
 - In the Site Collection section, select the site collection from the Site Collection list, and then select the site from the Site list.
 - If you are exporting a list, skip this step, Select the list or document library from the List list.
 - In the File Location section,
 - In the Filename box, type the UNC path of the shared folder and the file to which you want to export the list or document library.
 - The file name must use the .cmp extension.
 - If the file already exists and you want to use this file, select the Overwrite existing files check box.
 - Otherwise, specify a different file name.
 - If you want to export all the security and permissions settings with the list or library, in the Export Full Security section, select the Export full security check box.
 - If you want to specify which version of the list or library to export, select one of the following versions from the Export versions list:
 
- All Versions
 - Last Major
 - Current Version
 - Last Major and Last Minor
 
- Click Start Export.
 - You can view the status of all backup jobs at the top of the Granular Backup Job Status page.
 - You can view the status of the current backup job in the Content Export section of the page.
 - The status page updates every 30 seconds automatically.
 - You can manually update the status details by clicking Refresh. Backup and recovery are Timer service jobs. Therefore, it may take several seconds for the backup to start.