Abbreviating Science Journal Titles

Some citation / reference styles require you to abbreviate the journal titles when you're adding them to a bibliography. A couple of useful tools to help find the correct science journal abbreviations are:

CASSI (Chemistry)
Web of Science Journals 

If on the other hand you want to find the full journal title from an abbreviation use All that JaS. This resource (Journal Abbreviation Sources) lists the full titles of abbreviated journal titles and conference proceedings