If you are using Reference Manager 11 or any Network Edition of Reference Manager, you must close out of the database and reopen it in Read/Write Exclusive mode. To do so, close the database and go to "File > Open Database" and select "Read/Write Exclusive" in the "Access Rights" dropdown at the bottom of this dialog box, then open the database.

Additionally, if you are using Reference Manager 11, make sure you've updated to version 11.0.1.

Once this is done, follow these directions:

1. Go to "Tools > Term Manager > Activate" (for Reference Manager 10 and earlier, go to "Term Manager > Activate").
   
   
2. Click on the Periodicals tab to activate the Periodicals list.
   
   
3. Go to "Tools > Term Manager > Copy Periodicals" (for Reference Manager 10 and earlier, go to "Term Manager > Copy Periodicals").
   
   
4. In the "Copy From" dropdown, select the list you would like to copy from, Medical terms, Chemical terms, or Humanities terms.
   
   
5. Click "OK", and all the terms will be imported into your terms list, allowing for the substitution of the full name or abbreviated names. This substitution is determined by the output style you are using, so if the output style is set to use the Full journal name or the Abbreviated journal name, the correct journal names should now work with the style.

If for some reason the journal name in your actual reference doesn't match up exactly with the full name or one of the abbreviations in the terms list, the substitution will not take place.

If the above instructions have not resolved your problem, compare the journal name in your reference to the terms in the term manager and make sure you have an exact match. A single space or the inclusion of a period at the end of the name is enough for it to not be considered a match.