If the goal is to import just one list or one library there are a couple ways you can accomplish this:
1. Navigate to settings for the list or library, save it as a template, navigate to the solutions gallery, right click on the newly created template, save it as Windows SharePoint Services solutions package and then deploy that solutions package to your site, activate the feature, and begin using the list or library, Or,
2. Run this PowerShell, making sure to use the actual URL of the list or the correct name of the library. Surround this item in quotes
Export-SPweb http://mySitethathaslist/sites/ToExport -Item "Lists\Name of the list" -Path e:\PathToSaveFile\Filename.cmp -IncludeUserSecurity -IncludeVersions All
then copy that Filename.cmp to the destination server and run
Import-spweb http://anothersharepointblog.blogspot.com -Path e:\PathtoWheretheFilewasImported\FileName.cmp -includeUserSecurity -UpdateVersions Overwrite
Note: if the url to the list was actually lists/nameList then the Item part in the Export-spWeb above would’ve read “Lists\nameList” and not “Lists\Name of Lists”. Also if you are performing this for a document library, Lists\ is not needed.