MEDLARS^ The Computerized Literature Retrieval Services of the National Library of Medicine DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service National Institutes of Health The National Library of Medicine (NLM) is a part of the National Institutes of Health, one of the six health agencies of the Department of Health and Human Services' Public Health Service. The Li- brary was established in 1836 as the Library of the Army Surgeon General's Office and it remained in the military until 1956, when it was transferred to the Department and upgraded to be the Na- tional Library of Medicine. NLM is the world's largest research library in a single scientific and profes- sional field. Its holdings include over 2,500,000 books, journals, technical reports, theses, microfilms, and pictorial and audiovisual materials. Housed in the Library is one of the nation's largest medical history collections, with con- tents dating from the 11th to the mid- 19th century. This brochure describes for potential users the Library's computer-based literature retrieval services. These services represent but one of the Library's many information programs for the benefit of the health community. There are also programs of grant support for medical libraries, communications research and development, toxicology information services, development of audiovisu- al materials for health science education, and a wide range of published bibliographies, indexes, and catalogs. For more information write to: Office of Inquiries and Publications Management National Library of Medicine 8600 Rockvilie Pike Bethesda, Maryland 20209 Online Centers with Access to NLM Data Bases ALASKA © HAWAII © DISTRICT OF COLUMBIA AUSTRALIA CANADA ENGLAND FRANCE ITALY JAPAN MEXICO P.A.H.O. SOUTH AFRICA SWEDEN SWITZERLAND WEST GERMANY 0k Regional Medical Libraries C*\ Online centers per state Regional Medical Libraries Eleven Regional Medical Libraries, each responsible for a geographic area, coordi- nate NLM's online search services in the U.S. These libraries also handle requests for health literature not available locally, passing on to NLM requests they cannot fill. To find out the nearest Online Center, or how your institution can become a Center, write to the Regional Medical Library for your area. Region I New England Regional Medical Library Service (Connecticut, Mas- sachusetts, Maine, New Hampshire, Rhode Island, and Vermont) Francis A. Countway Library of Medicine Harvard University 10 Shattuck St, Boston, MA 02115 Region II New York and New Jersey Regional Medical Library New York Academy of Medicine Library 2 E 103 St, New York, NY 10029 Region III Mideastern Regional Medical Library Service (Delaware and Pennsylvania) Library of the College of Physicians 19 S 22 St, Philadelphia, PA 19103 Region IV Mid-Atlantic Regional Medical Library (District of Columbia, Maryland, North Carolina, Virginia, and West Virginia) National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20209 Region V Kentucky-Ohio-Michigan Regional Medical Library Program Wayne State University Shiffman Medical Library 4325 Brush St, Detroit, Ml 48201 Region VI Southeastern Regional Medical Library Program (Alabama, Florida, Georgia, Mississippi, South Carolina, Tennessee, and Puerto Rico) AW Calhoun Medical Library Emory University, Atlanta, GA 30322 Region VII Midwest Regional Medical Library (Illinois, Indiana, Iowa, Minne- sota, North Dakota, Wisconsin) Library of the Health Sciences University of Illinois at the Medical Center 1750 West Polk St. Chicago, IL 60612 Region VIII Midcontinental Regional Medical Library Program (Colorado, Kansas, Missouri, Nebraska, South Dakota, Utah, and Wyoming) Library of Medicine University of Nebraska Medical Center Omaha, NB 68105 Region IX South Central Regional Medical Library Program (Arkansas, Louisiana, New Mexico, Oklahoma, and Texas) University of Texas Health Science Center 5323 Harry Hines Blvd, Dallas, TX 75235 Region X Pacific Northwest Regional Health Sciences Library (Alaska, Idaho, Montana, Oregon, and Washington) University of Washington Health Sciences Library Seattle, WA 98195 Region XI Pacific Southwest Regional Medical Library Service (Arizona, California, Hawaii, and Nevada) Biomedical Library Center for the Health Sciences University of California at Los Angeles Los Angeles, CA 90024 Computerized Literal of the National Li Persons studying or working in the health sciences have access to the profes- sional literature by means of a computer- ized system known as medlars.* Based at the National Library of Medicine in Beth- esda, Maryland, medlars is available through a nationwide NLM network of centers at more than 1,300 universities, medical schools, hospitals, government agencies, and commercial organizations. Medlars contains some 4,500,000 ref- erences to journal articles and books in the health sciences published after 1965. Most of these references have been published via medlars in Index Medicus or in other printed NLM indexes and bibliographies. This same computer system also makes it possible for an individual user to search the store of references and to produce a list of them pertinent to a specific question. *A registered acronym for Medical Literature Analysis and Retrieval System. Terminals (keyboard de- vices that look like a type- writer) at each of the 1,300 institutions are connect- ed via commercial net- works of telephone lines to the Library's IBM 370/168 computers. To retrieve references, a user carries on a "dialog" with the computer, refining the search by typing in successive queries until the needed references are identified and printed out at the terminal. Such an "online" search, as it is called, usually takes about 10 to 15 minutes. There are a number of online data bases available through the online net- work. Each is described in a section below, beginning with medline (medlars online), the largest and most frequently used. References may be retrieved by searching on one or a combination of the 14,000 designated Medical Subject Head- ings (MeSH®) used by NLM in indexing and cataloging materials. It is also possible to search for references by using words appearing in titles and abstracts. The computer's ability to search rapidly through a large number of references to re Retrieval Services i rary of Medicine see which meet the specified criteria results in an individualized bibliography that would not be possible except by the most laborious and time-consuming man- ual search. The requestor may ask that the com- plete record be printed out for each reference retrieved—including the subject headings and abstract—or that a less detailed format include only the elements necessary to locate the item: author, title, and publication source. Articles or books identi- _if fied by computer search at fq^~l the online center may be J _f^ \ requested through that institution's library. Re- quests for items not avail- able locally are routed through an estab- lished network of 11 Regional Medical Libraries (see list). The National Library of Medicine provides copies or original loans of material that cannot be found in local or Regional Medical Libraries. The online search service is available to health practitioners, researchers, educa- tors, students—anyone faced with the difficult task of searching through the sci- entific and professional literature related to health. At many online centers the librarian will do the search for the reques- tor; at others, users may be encouraged to do their own searches after some prelimi- nary instruction. Complicated or difficult searches are best left to the center's specialists who have been trained in the techniques of searching. The charge for a search varies among centers. SSome absorb all or most of the costs, others levy a modest fee to recover the communication cost they incur for time connected to the NLM computers and for staff time. If a search results in an extensive bibliography that would be time-consuming (and therefore expensive) to print out at the terminal, it can be printed less expensively offline at NLM and mailed the next morning. The online center may recover the page charge for offline prints from the reques- tor. Data Bases Available Medline contajns approximately 600,000 references to biomedical journal articles published in the current and two preced- ing years. An English abstract, if published with the article, is frequently included. The articles are from 3,000 journals published in the U.S. and 70 foreign countries; medline also includes a limited number of chapters and articles from selected monographs. Coverage of previous periods (back to 1966) is provided by backfiles that total some 2,500,000 references. Medline can also be used to update a search periodically. The search formula- tion is stored in the computer and each month, when new references are added to the data base, the search is processed automatically and the results mailed from NLM. Toxline® (Toxicology Information Online) is a collection of 500,000 references from the last five years on published human and animal toxicity studies, effects of environ- mental chemicals and pollutants, and ad- verse drug reactions. Older material (663,000 references) is in two Toxback files. Almost all references in Toxline have ab- stracts or indexing terms and most chemi- cal compounds mentioned in Toxline are further identified with Chemical Abstracts Service Registry Numbers. The references are from three major published secondary sources and eight special literature collec- tions maintained by other organizations. Chemline® (Chemical Dictionary Online) is a file of 900,000 names for chemical substances, representing 450,000 unique compounds. Chemline, created by NLM in collaboration with Chemical Abstracts Service (CAS), contains such information as CAS Registry Numbers, molecular formu- las, preferred chemical nomenclature, and generic and trivial names. The file may be searched by any of these elements and also by nomenclature fragments and ring structure information, making chemical structure searches possible. RTECS (Registry of Toxic Effects of Chemi- cal Substances, formerly the Toxic Substan- ces List) is an annual compilation prepared by the National Institute for Occupational Safety and Health. RTECS contains acute toxicity data for approximately 41,000 substances. For some compounds there are also threshold limit values, recommended standards in air, and aquatic toxicity data. TDB (Toxicology Data Bank) contains chemical, pharmacological, and toxicolog- ical information and data on approximately 2000 substances. Information on an addi- tional 500 substances is being prepared. Data for the TDB are extracted from hand- books and textbooks and reviewed by a peer review group of subject specialists. Catline® (Catalog Online) contains about 210,000 references to books and serials cataloged at NLM since 1965. Catline gives medical libraries in the network immediate access to authoritative cataloging informa- tion, thus reducing the need for these libraries to do their own original catalog- ing. Libraries also find this data base a useful source of information for ordering books and journals and for providing reference and interlibrary loan services. Serline (Serials Online) contains biblio- graphic information for about 34,000 serial titles, including all journals which are on order or cataloged for the NLM collection. For one-fifth of these, serline has locator information for the user to determine which U.S. medical libraries own a particu- lar journal. Serline is used by librarians to obtain information needed to order jour- nals and to refer interlibrary loan requests. Avline (Audiovisuals Online) contains ci- tations to some 10,000 audiovisual teach- ing packages used in health sciences edu- cation at the college level and for the continuing education of practitioners. All titles in avline are screened for technical quality; all but lecture-type recordings are on the Online Network also reviewed for currency, content accu- racy, and teaching effectiveness. Avline may be searched by words in abstracts, medical subject headings, titles, names, source, and elements of physical descrip- tion such as medium and playing time. Health planning & admin (Health Plan- ning and Administration) contains about 170.000 references to literature on health planning, organization, financing, man- agement, manpower, and related subjects. The references are from journals indexed for MEDLINE, Hospital Literature Index, and other journals selected for their emphasis on health care matters. This data base will eventually also contain references to nonserial items such as books and techni- cal reports. Histline (History of Medicine Online) contains some 43,000 references to arti- cles, monographs, symposia, and other publications dealing with the history of medicine and related sciences. This data base is the source of NLM's annual Bibliography of the History of Medicine. Although there are selected references back to 1964, most of the material cited in the histline file was published after 1970. Cancerlit (Cancer Literature), formerly called cancerline, is sponsored by NIH's National Cancer Institute (NCI) and con- tains more than 250,000 references dealing with various aspects of cancer. All referen- ces have English abstracts. Over 3,000 U.S. and foreign journals, as well as selected monographs, meeting papers, reports, and dissertations are abstracted for inclusion in CANCERLIT. Cancerproj (Cancer Research Projects), also sponsored by NCI, contains 20,000 de- scriptions of ongoing cancer research proj- ects from the current and two preceding years. The descriptions are provided by cancer researchers in many countries and are collected for NCI by the Smithsonian Science Information Exchange. Clinprot (Clinical Cancer Protocols) is another NCI-sponsored data base. It contains summaries of clinical investiga- tions of new anticancer agents and treat- ment techniques. Bioethicsline is a file of about 11,000 refer- ences to materials on bioethical topics such as euthanasia, human experimentation, and abortion. They are selected from the literature of the health sciences, philo- sophy, law, religion, psychology, and from the popular media. Bioethicsline is pro- duced in cooperation with the Kennedy Institute of Ethics, Center for Bioethics, at Georgetown University. Epilepsyline is sponsored by NIH's National Institute of Neurological and Communica- tive Disorders and Stroke. The file contains about 37,000 references and abstracts to articles on epilepsy that have been ab- stracted by Excerpta Medica. Popline (Population Information Online) is produced in cooperation with the Office of Population, U.S. Agency for Internation- al Development. It contains about 75,000 citations to journal articles, monographs, and technical reports in the field of popu- lation—including basic research in repro- ductive biology, applied research in con- traceptive technology, family planning, and demography. Two subsidiary online files that sup- port the bibliographic data bases are the Name Authority File (an authority list of about 106,000 personal names, corporate names, and decisions on how mono- graphic series are classed), and the MeSH Vocabulary File (information on 14,000 Medical Subject Headings—main headings and qualifiers—used for indexing and retrieving references). NIH Publication No. 81-1286 Revised March 1981 GPO : 1981 0 - 339-960