Medical Subject Headings (MeSH)

Medical Subject Headings (MeSH) is a hierarchically-organized terminology for indexing and cataloging of biomedical information. It is used for the indexing of PubMed and other NLM databases. Please see the Terms and Conditions for more information regarding the use and re-use of MeSH. NLM produces Medical Subject Headings XML, ASCII, MARC 21 and RDF formats.

Updates to the data files are made according to the following schedule:

MeSH XML
MeSH Descriptor files updated annually
MeSH Qualifier files updated annually
MeSH Supplemental Concept Records (SCR) updated daily (Monday - Friday)

MeSH ASCII
MeSH Descriptor files updated annually
MeSH Qualifier files updated annually
MeSH Supplemental Concept Records (SCR) updated daily (Monday - Friday)

MeSH MARC21
All files posted monthly

MeSH RDF
All files posted daily (Monday - Friday)

医学主题词表（MeSH）是一种按层级组织的信息生物医学术语体系，用于对生物医学信息进行索引和编目。该体系被用于PubMed及其他NLM数据库的索引。有关MeSH的使用与再利用条款，请参阅相关条款和条件。NLM提供MeSH的XML、ASCII、MARC 21和RDF格式。数据文件的更新按照以下时间表进行：

MeSH XML
MeSH描述符文件每年更新一次
MeSH限定符文件每年更新一次
MeSH补充概念记录（SCR）每周一至周五每日更新

MeSH ASCII
MeSH描述符文件每年更新一次
MeSH限定符文件每年更新一次
MeSH补充概念记录（SCR）每周一至周五每日更新

MeSH MARC21
所有文件每月发布一次

MeSH RDF
所有文件每周一至周五每日发布。