You can't import them, but you can copy and paste all layout objects from one file to another. This requires a tedious attention to detail starting with the name of the table occurrence specified in Layout Setup | Show Records From in your two layouts as the exact same name should be specified for both source and target layouts. (sometimes you have to temporarily rename an occurrence box in Manage | Database | relationships until you get your new layout correctly functioning). If you have fields on your layout from related table occurrences, their names need to match in the two files as well.
For a step by step of the whole process, see: Importing Layouts