LiveJournal does not provide any way to add a large number of entries from another site or journal to your LiveJournal simultaneously.
You cannot automatically import entries or comments into your LiveJournal from another LiveJournal account or an account on another site. This is true even if you have downloaded your entries from that site or journal
to your computer and regardless of whether the other site runs LiveJournal code.
The only way to add an entry from another journal or another site to your LiveJournal is to copy and paste the entry's text into the Post an Entry
page. When doing this, you can set the appropriate date and time for the entry by changing the values in the "Date:" fields on the Post an Entry page. Adding an entry in this way will cause it to appear in your journal as though it were originally posted there on the date you specified. If you choose to do this, you may need to enable the "Do not add to friends page and RSS" option
; this will also prevent your friends' Friends pages from being flooded with the new entries.
While this method will let you add entries to your journal, it will not work for transferring comments attached to those entries. You can, however, include a link
to the original entry and its comments in the update.
If you want to use the above method to copy a large number of entries from another journal to your LiveJournal, you may wish to use a downloadable client
to add the individual entries to your journal, which would eliminate the wait for pages to load and the need to copy and paste. Note that a downloadable client isn't guaranteed to work for transferring entries to or from an external site.