MEDLARS: A computerized biomedical bibliographic storage and retrieval system operated by the NATIONAL LIBRARY OF MEDICINE. MEDLARS stands for Medical Literature Analysis and Retrieval System, which was first introduced in 1964 and evolved into an online system in 1971 called MEDLINE (MEDLARS Online). As other online databases were developed, MEDLARS became the name of the entire NLM information system while MEDLINE became the name of the premier database. MEDLARS was used to produce the former printed Cumulated Index Medicus, and the printed monthly Index Medicus, until that publication ceased in December 2004.National Library of Medicine (U.S.): An agency of the NATIONAL INSTITUTES OF HEALTH concerned with overall planning, promoting, and administering programs pertaining to advancement of medical and related sciences. Major activities of this institute include the collection, dissemination, and exchange of information important to the progress of medicine and health, research in medical informatics and support for medical library development.Bibliography as Topic: Discussion of lists of works, documents or other publications, usually with some relationship between them, e.g., by a given author, on a given subject, or published in a given place, and differing from a catalog in that its contents are restricted to holdings of a single collection, library, or group of libraries. (from The ALA Glossary of Library and Information Science, 1983)Bibliography of Medicine: A list of works, documents, and other publications on medical subjects and topics of interest to the field of medicine.Information Systems: Integrated set of files, procedures, and equipment for the storage, manipulation, and retrieval of information.Abstracting and Indexing as Topic: Activities performed to identify concepts and aspects of published information and research reports.Library Administration: Planning, organizing, staffing, direction, and control of libraries.Rosaceae: The rose plant family in the order ROSALES and class Magnoliopsida. They are generally woody plants. A number of the species of this family contain cyanogenic compounds.Subject Headings: Terms or expressions which provide the major means of access by subject to the bibliographic unit.Crataegus: A genus in the family ROSACEAE of shrubs and small trees native to the North Temperate Zone. It is best known for a traditional medication for the heart.Libraries: Collections of systematically acquired and organized information resources, and usually providing assistance to users. (ERIC Thesaurus, http://www.eric.ed.gov/ accessed 2/1/2008)ComputersAutomatic Data Processing: Data processing largely performed by automatic means.Libraries, MedicalHistory, 20th Century: Time period from 1901 through 2000 of the common era.United States