NLM Classification Updated for 2009

A newly revised edition of the National Library of Medicine Classification adds 17 new class numbers to the main schedules and four new class numbers to the 19th Century schedule. The NLM Classification was updated April 23, 2009.

In addition, one class number was canceled; 81 MeSH terms were added to the index, including 34 new to the MeSH vocabulary as of 2009; and 71 schedule records and 508 index entries were updated since the 2008 edition was published on April 24, 2008.