ASCII MeSH, 2003. Documentation and Availability

1. ASCII MeSH

ASCII MeSH contains all data that were present in ELHILL MeSH,* including cross-references and scope notes. Descriptions of the data elements in each file are available for each of the three record types:

See MeSH ELHILL Format Document (PDF format) for an additional description of the data elements, including most of those found in the ASCII MeSH file. *Note that ELHILL MeSH is no longer in production.

2. Restrictions on use.

There is no charge. Use of the ASCII MeSH file data is subject to conditions which are detailed in the Memorandum of Understanding .

3. Availability

The data for Descriptors and Qualifiers are updated annually and users of the data are encouraged to obtain the new year's data. Any changes made mid-year are included in the weekly update of ASCII MeSH files.

Supplementary Concept Records (formerly Supplementary Chemical Records) are updated at NLM on a daily basis. The current file in ASCII MeSH is updated weekly and is coordinated with 2003 MeSH descriptors so that the data elements that require a descriptor MH value, such as the HM element, have been updated to match a descriptor in 2003 MeSH. New records will be added to ASCII MeSH periodically.

MeSH Descriptors and Qualifiers are also published annually in print as the Medical Subject Headings, Annotated Alphabetic List. Some Descriptor data are also published in Medical Subject Headings, Tree Structures and Permuted Medical Subject Headings . These publications for 2003 MeSH are expected to be available from NTIS in late November 2002.

4. File format

Each MeSH record is indicated by a separate line, preceding the record, consisting of the string

*NEWRECORD

Each element or occurrence is contained on a single line. Each line contains an element name and value, for example,

MH = Appendicitis

The same is true for longer, free-text fields such the Annotation and Scope Note. (The longest occurrence/line in the files is in the descriptor file and is 1124 characters.)

For data elements that are multiply-occurring, each element occurs on a separate line, for example, the MeSH Tree Number:

MN = E05.200.500.607.790
MN = E05.200.500.620.670.620

Almost all data in ASCII MeSH files are in 7-bit ASCII format. The only exception is that in 39 descriptor records, the Annotation element contains one or more diacritical characters. These are coded in UTF-8 format and will be correctly displayed by UTF-8 applications. Otherwise they may appear differently in different displays.

The file extensions are .bin rather than .txt so that Web browsers will prompt to save rather than automatically trying to display the relatively large text files (up to 42MB). The lines will usually be transmitted with only a line feed character (decimal 10) and not also a carriage return (decimal 13). Please contact the MeSH Section at the address below if you have questions.

5. Contents of files. 2003 MeSH. Files updated weekly.

Record Type	Total Records	File Size	Bytes
Descriptors	21,973	22MB	23,272,728
Qualifiers	83	102KB	104,600
Supplementary Concept Records **	131,331	43MB	44,967,765

** Formerly Supplementary Chemical Records.

6. For questions concerning the content of ASCII MeSH, contact:

Stuart Nelson, M.D.
Head, Medical Subject Headings
National Library of Medicine
8600 Rockville Pike
Bethesda, MD 20894

voice: 301-496-1495; FAX: 301-402-2002
email: nelson@nlm.nih.gov

For questions concerning distribution, format, etc., contact:: Jacque-Lynne Schulman; Medical Subject Headings; voice: 301-496-1495; FAX: 301-402-2002; email: schulman@nlm.nih.gov

Last updated: 15 October 2002