Since Journals have full names and abbreviations, you'll want EndNote to know how to manage all the variations.
This is not a requirement, but if you find that your are not seeing journal abbreviations presenting as they should, you may need to update your terms list. Watch this video to learn how to set up a journals term list to make journal names consistent in bibliographies--even if they are not consistent in the library records.
"EndNote provides a number of terms list to make sure that the journal names in your bibliography are either the full name or abbreviation as your style requires. To set up your terms list, first make a backup of your library as described at EndNote: Moving, backing up, or transferring libraries to another computer Then, please follow the steps at the Endnote Support Site: