Searching for Medical Literature

Transcription

1 Searching for Medical Literature Grace A. Ajuwon, MLS, Ph.D E. Latunde Odeku Medical Library, College of Medicine, University of Ibadan University of Ibadan Medical Education Partnership Initiative Junior Faculty Initiative Research Training Programme (UI-MEPIN-J) Bibliography Workshop 11th April,

2 How to Scope your Search What is your topic? Define each of the areas clearly Write down list of questions you are trying to answer What sort of information do you need to answer the questions? What areas of the world are you interested in? Is there anything about the population that is important (i.e., gender, age, ethic background)? How recent do you want the information to be? Information Sources 2

3 Information Sources Choosing the Right Resource (s) to Search 3

4 Online Information Searching Tools Library Catalogues Indexes and Abstracts Search Engines Databases Gateways Portals Digital Archives Institutional Repositories 4

5 Bibliographic Databases MEDLINE/PubMed Web of Science EMBASE Science Direct EBSCO Host Academic Premier African Index Medicus The Cochrane Library MedlinePlus Starting point: Search Preparation Develop a search topic Define clearly and concisely the search objective Identify the key concepts/keywords in topic Decide the focus of the topic- General or specific Have a time span 5

6 Define the Topic Clearly Define the search topic clearly Formulate the search statement or search question in full E.g. malaria in infection in children in Africa Breakdown the research topic into main components or keywords Concepts/keywords - malaria, infection, children, Africa Use search techniques where appropriate Choose Appropriate Keywords In keyword searching, take into consideration the following: Key concepts of the research question or topic Related terms or Synonyms (e.g. adolescent or teenage; mobile phones or cellular phones) Variations in word spelling English or American (behaviour / behavior) Variations in word endings- plural or singular (e.g. Woman, women) Variations of a root word (e.g. feminism, feminist, feminine) Acronyms HIV/AIDS or full names Most search tools (e.g. PubMed) use keywords for information retrieval 6

7 Search Strategy Formulate Search Strategy A search strategy is a plan that help to articulate the information required and covers areas such as: Purpose of the information -The best sources/tools to choose from -What is the geographical location Publication period- currency Focused or general information Types of Searches Simple or Basic search Use keywords to perform a quick information search from a Database OR search engine One or two concepts can be used to perform a simple search Huge amount of information is retrieved Advanced search Uses techniques that help define the information being searched Some filtering is done to refine the search for relevancy and to reduce the number of items retrieved Multiple search fields can be applied to broaden or narrow the search Meta search This is done with the use of Meta search engines such as Dogpile, Search.com; Metacrawler and Vivisimo Meta search engines search across different search engines simultaneously 7

8 Keyword Search Keywords are words and phrases used by the author or indexer to closely describe the topic or subject. Keyword can be used to search databases (e.g. MEDLINE/PubMed) or search engines (e.g. Google, Yahoo, Alta Vista etc) In keyword search, the Basic or Advance search options can be used Example 1: Malaria infection in pregnant women in Africa Keywords/Concepts: Malaria, infection, pregnant women, Africa - Search Results: PubMed= Exact match in PubMed=3 citations Google= 531,000 Search techniques are the various methods employed in conducting a focused online literature search Types of Search Techniques: Boolean Logic (AND, OR, NOT) Field searching Phrase searching Parenthesis Search Techniques Truncation and wildcards Controlled vocabulary e.g. MeSH Subheadings 8

9 Use of Boolean logic Boolean logic uses the following operators: OR, AND, NOT OR - Broadens the search AND Narrows and focuses the search NOT excludes unwanted words or concepts to focus the search Uses Venn diagrams to illustrate the logical relationship Boolean operators are presented in upper case Some search tools use plus (+) and minus (-) signs to represent the Boolean operators Example: 1: AIDS AND adolescents AND Nigeria 2. HIV OR AIDS 3. Malaria NOT fever Boolean Operator: AND AND links words or phrases that both appear in the same article If you want to focus your search results, use Boolean operator AND to connect additional word(s) Example: Exercise AND Aged -- finds both exercise and aged anywhere in the same article Grace Ajuwon, E. Latunde Odeku Medical Library, UI, Ibadan 9

10 Boolean Operator: OR OR links synonyms, alternative forms of expression, acronyms, and so on If you want to expand your search, use Boolean operator OR to connect additional word(s) Example: Diet or Nutrition -- finds either diet or nutrition in the same article OR is suitable when keyword has a synonym Grace Ajuwon, E. Latunde Odeku Medical Library, UI, Ibadan Boolean Operator: NOT NOT excludes words or phrases from your search If you want a word or phrase to be excluded from your search, use the NOT operator Example: Exercise NOT Therapy --- finds exercise in the same articles, exclude therapy Malaria NOT Fever --- retrieves only articles on malaria and excludes articles on fever Grace Ajuwon, E. Latunde Odeku Medical Library, UI, Ibadan 10

11 Field Searching Electronic records are presented as fields Database fields include: title author affiliation journal or book title, abstract language Any of the fields can retrieve information from a search tool Field searching is focused e.g. author search Search tools limit search according to fields - author, abstract, language, year of publication, affiliation e.g. PubMed PubMed provides a template for field searching by users Example of PubMed field search statement: Ajuwon GA [au] Phrase Searching In phrase searching, the keywords or concepts to be searched are enclosed in quotes.. The quotation marks instructs the search engine to search only words that appear side by side inside the quotes Phrase searching narrows down search results significantly, more relevant results are retrieved Example 1: A phrase search in Google -: HIV/AIDS and tuberculosis retrieved 160,000 records. HIV/AIDS Tuberculosis retrieved 351,000 records Without the quotes: HIV/AIDS and tuberculosis retrieved 8,020,000 records HIV/AIDS tuberculosis retrieved 8,720,000 records 11

12 Phrase Searching: PubMed PubMed searches for phrases under these conditions: 1. The phrase is entered with a search tag: Kidney allograft [tw] Ajuwon GA [au] 2. The phrase is enclosed in double quotes: kidney allograft Pressure point 3. The term is hyphenated: First-line 4. The term is truncated: Kidney allograft* PubMed Phrase Search In PubMed, phrase searching may lead to omission of relevant citations Why? because it bypasses Automatic Term Mapping Use Index of Searchable Terms MeSH Translation Table Journal Translation Table Author Index Example: PubMed phrase search 1. "HIV AIDS" "tuberculosis" retrieved 2156 records 2. Searching HIV AIDS tuberculosis without the quotes retrieved 7726 records 3. HIV/AIDS tuberculosis retrieved 8072 records 12

13 Use of Parenthesis This search technique is used to force the order of how information is retrieved Results returned through the use of parenthesis are more relevant Parenthesis uses more than one Boolean operator It is used to perform complex searches For example, in PubMed, retrieval of information related to diabetes prevention and control can be searched thus: 1. Breast cancer AND (prevention OR control) = 63,751 records 2. Breast cancer AND (prevention AND control) = 25,111 Without the use of parenthesis Breast cancer AND Prevention OR control = **** records Use of Truncation Truncation is the process of using an asterisk mark (*) while searching The purpose of truncation is to broaden the search Through the use of truncation at the root of the word, the search tool searches all word variations after the asterisk Asterisk may only be used at the end of a string of characters Example: Child* = retrieved information on child, children and childhood Example: Mimick* will find all terms that begin with the letters m-i-m-i-c-k E.g. mimick, mimicks, mimicked, mimicking Each search tool treats the use of search techniques differently It is therefore advisable to check if the search tool allows the use of truncation PubMed and Google uses the following Truncation symbols: $,!, # 13

14 Examples Searches using Truncation Symbols Search Topic Truncation Symbol PubMed Google Malaria infection child* Africa Malaria infection child$ Africa Malaria infection child! Africa Malaria infection child# Africa * 1 19,000,000 $ ! ,600,000 # ,600,000 Use of Wild Cards Wildcards are characters that are used to assist in searching for information Wildcards are used to represent one character or letter in a word Wildcards are especially useful in situations when the user is not sure of the correct spelling of a word In medicine, there are variations in the use of American and English word spelling for medical terms The most commonly used wildcard is? It is advisable to check the wildcard symbols used by each search tool or search engine Example 1. An?mia will retrieve Anaemia, Anemia 2. Colo? will retrieve Colour and Color 14

15 Use of Controlled Vocabulary (MeSH) Pre-defined "controlled vocabulary" words assigned to describe the content of each item in a database or catalog Less flexible. You must know the exact controlled vocabulary term or phrase Database looks for subjects only in the subject heading or descriptor field, where the most relevant words appear If a subject heading search yields too many results, you can often select subheadings to focus on one aspect of the broader subject. Results are usually very relevant to the topic A controlled vocabulary makes a database easier to search Makes database searching more efficient as it eliminates guess work However, this efficiency requires consistency on the part of the individual indexing the database and the use of pre-determined terms Example: Ear pain Indexed Ear ache (with subheadings) Why Search Bibliographic Databases - MEDLINE/PubMed? Information is well organized Information is filtered and indexed Selection criteria applied by experts Information is from known sources such as peer reviewed journals, books and credible institutions Allows use of search techniques for more focused search results 15

16 Searching PubMed/MEDLINE Connect to PubMed through Use your institutional User Name and Password to login User Name: Password: Access e-books or journals using alphabetical links Select the hyperlink search for articles through PubMed You can also access PubMed at: Requirements for Successful Information Retrieval Define the search problem Develop a search strategy Use search techniques Learn how to use search tools e.g. PubMed, Cochrane Library, search Engines (i.e. Google) Consider other forms of information sources such as print and audio-visuals Evaluate retrieved information 16

17 Criteria for Evaluating Information Authority/Source Accuracy Audience Purpose Currency/Timeliness Objectivity Organization and Management of Information Organize and manage retrieved information using reference manager tools Cite and arrange bibliographic references using: Endnote RefMan Procite Mendeley CiteULike Connetea 17

18 Knowing is not enough; we must apply. Willing is not enough; we must do. Goethe My Contact Info