How to make a literature search

Introduction about basic search methods and how to use catalogues, databasses and other internet sources

Content

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1. Developing a Search Strategy

• Make brainstorming before you start and try to structure your ideas• Identify main and side aspects to your search and try to find major and minor keywords• Think of synonyms and variations (e.g. grammar, plural) of your keywords• Use a dictionary or a handbook to get an overview.

a) Defining the Topic

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b) Choose Keywords and Search Strategy

• Strategy 1: “Blockbuilding-approach (BBL)“ Means to split your search topic in single terms

• Strategy 2: “Citation pearl growing approach“ Means you start with a known citation, may be a key-article and reuse this keywordsm, subject- headings, reference list to find more articles. Like a snowball system.

• Choose the appropriate source for searching Dependent on questions like „Do I need the latest infor- mation?“, “Is my topic very specific or more general?“, “What kind of publication do I need?“

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c) Combining Keywords

In Databases, Catalogues and Search engines single terms are combined with so called “Boolean Operators“

• AND

A AND B

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• OR

A OR B

• NOT

A NOT B

• Depending on your result you have to vary your search with different search terms

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d) Vary your Search

• A search means always a brinkmanship of finding too much or too less

• Rule: The more complete your search should be, the more irrelevant hits will be included. On the other hand, in case all hits are relevant, then it is likely that there are more hits which are excluded by your search strategy.

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2. Databases

a) What is a database?

• An organized collection of information to a special field or subject• Organized means all documents are indexed with special descriptors or subject headings

Bibliographic databases contain descriptive information about publications Fulltext databases are including them

Keyword Means in general a search term that is somewhere included in the document (title, abstract, author, adress field …)A search done only with keywords can be unspecific and may have many irrelevant hits.

Subject Heading orDescriptor

A subject heading or descriptor corresponds to the content of the document.People (normally called documentalists) have read and indexed the documents

Thesaurus A Thesaurus is a structured systems of subject headings. Subject headings are connected with broader and narrower terms (Tree structure).

Controlled vocabulary, no synonyms.The Thesaurus in MEDLINE is called “Medical Subject Headings = MeSH

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Some important terms that are related to databases (and catalogues)

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Tree-structure for term “Smoking“ in PubMed

Producer NLM = National Library of Medicine, USA

Type Bibliographic Databases with Abstracts (67%)

Indexed Sources Journal articles of more than 4000 Journals. Yearly increase of 400 000 new articles.90% articles are in english language. 50% sources are from the USA

Regional Focus Anglo-american Region

Subject coverage Clinical Medicine, Biological Sciences, Pharmaceutics,

Veterinary Medicine, Genereal Health Sciences

Access Free acces by Internet

Actuality About 3 month for complete indexing. Incomplete, without descriptors partly after 2 weeks (e.g. BMJ, Lancet …)

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b) Database profilesMEDLINE (Version PUBMED)

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Entry page of PUBMED

Producer Johns Hopkins School of Public Health, Baltimore, Md., USA

Type Bibliographic database with abstracts (67%)

Extent 300 000 documents, annual increase of 10 000.Since 1980

Indexed Sources Journal articles, Books, Book Chapters, Unplished Reports, Articles in Newspapers, Dissertations, Confernce Papers

Regional Focus World with Anglo-american focus

Main subjects Family Planning, Reproductive Health, AIDS

Access Free access by Internet

Other features Own document delivery service (for Developing Countries free of charge)

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POPLINE

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Entry page of POPLINE

Producer BIREME, Brasil

Type Bibliographic database with abstracts

Extent 150 000 documents, annual increase of 7000.Since 1982

Indexed Sources Journal articles, Books, Book Chapters, Unpublished Reports, Conference Papers

Regional Focus Latin America and Caribean ; Language: span. + engl.

Main subjects Heath Sciences

Access Free access by Internet

Other features Own document delivery service. Uses same Thesaurus as Medline. Free access to some articles.

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LILACS

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Entry page of LILACS

Producer WHO + Association for Health Information Libraries in Africa

Type Bibliographic database

Extent 5 000, annual increase of less than 100.Since 1980

Indexed Sources Journal articles, Unpublished Reports

Regional Focus Africa

Main subjects Medicine in Africa

Access Free access by Internet

Sonstiges Database is under construction. Some articles are free available online

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Index Medicus Africa

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Entry Page of African Index Medicus

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3. Catalogues

A catalogue is more incomplete than a database.In opposite to bibliographic databases it includes only documents that are locally available and gives information about their location.

Online resources can also be part of a catalogue, even ifthey are located somewhere else.

Catalogues

HEIDI Catalogue of the University Library of Heidelberg. Includes branch libaries and departmental libraries of Heidelberg.

WHOLIS Catalogue of WHO. Includes free online access to WHO documents

ZDB Periodical and serial catalogue for Germany. Important for interlibary-loan.

KVK Makes a multiple search in several national and international catalogues

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Links see Chapter “LINKS“

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Search menu of „HEIDI“

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Search menu of „WHOLIS“

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4. Internet Sources

a) Search engines

Search engines are programmes that are searching the World Wide Web and finding and indexing sites.In spite of the enormous number of hits, it is estimated that search engines are only finding 5% of the complete WWW (the rest ist so called Deep or Invisible Web).

Not searchable are:

In Databases and Catalogues stored informationProtected Websites Dynamic Websites

General Search EnginesGoogle Most used Search engine

Altavista Similiar to google. But different hits and also different ranking

Vivismo Feature: is structuring the search result

Meta Search Engines

Webcrawler Is searching simultaniously in Google, Altavista and other common search engines

Excite Similar to Webcrawler

Special Search EnginesGoogle Scholar Provides search for scholarly literature. Search articles are

ranked where they have been appeared and how often they have been cited.

Scirus Search engine for sciences. Sites are ranked dependend how many links are leading to the sites back. Has more links to (not free available) journal articles of publishers.

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Citebase Search Search engines for for free available documents in the Internet

PubMed Central Part of Medline/IndexMedicus. Search is limited here to free available documents

Biomedcentral Open-Access-Journals. Peer-reviewed journals as commer-cial publishers. Philsophy: Free access. Financed by author-fees and their scientifc institutions

PLOS Open-Access-Journals. Similar to “Biomedcentral“

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b) Open Source

Databases

Medline (PUBMED) http://www.pubmed.com

POPLINE http://db.jhuccp.org/popinform/basic.html

LILACS http://bases.bireme.org

Index Medicus Africa http://indexmedicus.afro.who.int

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5. LINKS

Catalogues

HEIDIhttp://www.ub.uni-heidelberg.de/helios/kataloge/heidi.html

WHOLIS http://dosei.who.int

ZDB http://dispatch.opac.d-nb.de/

KVK http://www.ubka.uni-karlsruhe.de/hylib/en/kvk.html

Document-Delivery-Services

SUBITO (only D) http://www.subito-doc.de

BL Doc. Suppl. Cent (Int.)

http://www.bl.uk/reshelp/atyourdesk/docsupply/index.html

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Search Engine (general)

Google http://www.google.com

Altavista http://www.altavista.com/

Vivisomo http://vivisimo.com/

Metagears

Webcrawler http://www.webcrawler.com

Excite http://www.excite.com/

Special Search Engines

Google Scholar http://scholar.google.com

Scirus http://www.scirus.com

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Open Source

Citebase Search http://www.citebase.org/cgi-bin/search

PUBMedCentral http://www.pubmedcentral.nih.gov/

BiomedCentral http://www.biomedcentral.com/

PLOS http://www.plos.org/

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6. Excercisesa) Bibliographic Search

Find the follow articles / books. Use the appropriate catalogue!1.Reinke, William A.: Health planning for effective managementNew York, Oxford: Oxford Univ. Press, 1988. - ISBN 0-19-505337-0

2.Cook, J.A.: Tropical medicine and health in the developing worldAm J Trop Med Hyg. 38. 1998 : 459-65

3.Bennett, Sara ; Creese, Andrew ; Monasch, Roeland:Health insurance scheme for people outside formal sector employment. Geneva: World Health Organization, 1998WHO/ARA/CC/98.1

4. AbouZahr, Carla : Maternal mortality overviewIn: Health dimensions of sex and reproduction. Ed. by Christopher L. Murray ... Geneva: World Health Organization, 1998. pp. 111 – 164. – (Global burden of disease and injury series)

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b) Subject Search

Use Medline/PubMed to find articles to the following topics:

1. Chloroquine-resistant Malaria in Tanzania

2. Studies on the introduction of charges for health care in developing countries

3. Assessment of nutritional status in infants and preschool children

Try to mark and download or print relevant articles

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1. Find statistics on the prevalence of AIDS in Africa (Try UNAIDS site via WHO website)

2. Find at least one article from Mr. Rainer Sauerborn about childhood mort- ality in Burkina Faso. How often is this article cited from other persons in their articles?

Use search engines to find …

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Search example

Cost-effectiveness of immunization programmes in Africa

Ideas what can be part of this this topic:

Search terms:

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Steinbrock, R. Serching for the right search – reaching the medical literature. New Engl J Med. 2006; 354(1): 4-5

Guistini, D. ; Barsky, E. A look at Google Scholar, PubMed and Scirus: comparisons and recommendations. JCHLA / JABSC. 2005: 26: 85-89

Eyers, J.E. Sources of information in tropical medicine. In: Cook, G.C.(ed.) Manson‘s tropical diseases, 21st. ed. London: Saunders, 2002 : 1807- 1815

Eyers, J.E. How to do (or not to do)… Searching bibliographic databases effectively. Health Pol Plann 1988; 13(3): 339-342

References