Some journal require you to use the abbreviated names for journals. If you have to change this manually, it's quite cumbersome to do. Luckily there exist tools to help. Jabref is open source bibliography reference manager. It has an option to abbreviate journal names. However, when it comes to Physics journals, the internal list is far from complete.
I have converted the list of abbreviations from ISI to a Jabref readable format. The file is in UTF-8 as some journal names have non-ascii characters.
To abbreviate the journal names, have a look at http://jabref.sourceforge.net/help/JournalAbbreviations.php Jabref can automatically download the file for you. Enter as url: https://raw.githubusercontent.com/wpoely86/jabref-abbreviations/master/list-abbreviations.txt