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Doing Literature Review


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The literature review usually precedes a research proposal and results section. Its goals are to situate the current study within the body of literature and to provide context for the particular reader. Literature reviews are important for research in nearly every academic field.

Published in: Education, Health & Medicine
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Doing Literature Review

  1. 1. Doing Literature Search
  2. 2. Records, Files, Data
  3. 3. To Know: Value of research What to search How to search
  4. 4. Baguio Gen Hosp
  5. 5. 21 National Library of Medicine  The world’s largest biomedical library  NLM is the producer of:  MEDLINE  PubMed   Visit the National Library’s Home Page at: 
  6. 6. PUBMED  Provides free access to medical database  Links to full-text articles  Provides Advanced search  Links to related articles and provides discovery tools for other data that may be of interest.
  7. 7. PubMed’s Sponsor  Introduction to the U.S. National Library of Medicine (NLM)  The National Network of Libraries of Medicine®  NN/LM Web site:
  8. 8. What’s in PubMed  Most PubMed records are MEDLINE citations.  Other records include those in different stages of processing (including records provided directly from the journal publisher) but destined to be MEDLINE citations.  A relatively small number of records that are included in PubMed but not selected for MEDLINE.
  9. 9. 25 What is MEDLINE?  The world’s largest biomedical database  MEDLINE covers:  Medicine  Dentistry  Veterinary Science  Nursing  Other Biological Sciences
  10. 10. 26 What is MEDLINE?  4,800 journals are indexed  Covers all aspects of biosciences and healthcare  Database of 14+ million journal citations
  11. 11. 27 What is MEDLINE?  Covers 1966 to the present  Coverage worldwide, 85% are in English  76% have abstracts
  12. 12. MEDLINE  MEDLINE is NLM's bibliographic database of citations and abstracts, currently  > 5,600 biomedical journals All citations in MEDLINE are assigned
  13. 13. MEDLINE Citations  PubMed provides access to MEDLINE  Scope of MEDLINE includes such diverse topics as microbiology, delivery of health care, nutrition, pharmacology and environmental health. The categories covered in MEDLINE include everything from anatomy, organisms, diseases, psychiatry, and psychology to the physical sciences.  contains over 17 million references dating back to 1948.  New material is added Tuesday through Saturday.
  14. 14. MeSH  National Library of Medicine's controlled vocabulary thesaurus.  consists of sets of terms naming descriptors in a hierarchical structure that permits searching at various levels of specificity.
  15. 15. 33 What is MeSH?  MeSH – Medical Subject Headings  Controlled vocabulary terms ○ Brain Edema, Otitis Media, Myocardial Infarction
  16. 16. Practice Exercises Introduction to MeSH
  17. 17. 1.If you search the term “phytotherapy” in PubMed, what terms are you also searching?
  18. 18. ANSWER 1. If you search the term “phytotherapy” in PubMed, what terms are you also searching?  Aromatherapy and Eclecticism
  19. 19. 2.How far back can you search with the MeSH term, “Proteomics?”
  20. 20. ANSWER 2. How far back can you search with the MeSH term, “Proteomics?”  To 2003. For 2000-2002, use Proteome.
  21. 21.  3. What ages are included by the term, “Child?”
  22. 22. ANSWER 3. What ages are included by the term, “Child?”  6 to 12 years.
  23. 23. 4. What is the preferred MeSH term for “chewing?”
  24. 24. ANSWER 4. What is the preferred MeSH term for “chewing?”  Mastication.
  25. 25. 44 How do I access PubMed?  Directly at:  Or, National Library of Medicine’s homepage:
  26. 26. 45 PubMed Screen Layout Feature Tabs Query Box aka Search Box Blue Sidebar
  27. 27. 46  Translates lay terms into medical subject headings  Heart Attack into Myocardial Infarction  Links to selected free articles through publishers’ web sites  Most articles are written for health professionals
  28. 28. BOOLEAN
  29. 29. Boolean Strategies - If you are retrieving too many records on your topic, try adding another search term with the connector AND.

  30. 30. Boolean Strategies If you are retrieving too few records on your topic, try adding another search term with the connector OR.
  31. 31. Boolean Strategies If you are retrieving too many records on an unrelated topic, try eliminating a word with the connector NOT.
  32. 32. Truncation & Wildcards  To increase the number of hits retrieved, you might consider using a truncation symbol. Truncation will pick up variations of a word stem. Truncation symbols vary, depending on the database.  
e.g., critic* will find critic, critics, criticism, critical, etc.  
The wildcard symbol can be used to replace one letter in a word. This will instruct the computer to do a search and match all letters in the word and use any letter to replace the wildcard symbol.  
e.g., Wom?n will retrieve records with woman and women.
  33. 33. Basic Searching Quotation Marks “ “ Requires words to searched as a phrase, in the exact order you type them. Common Words Usually Ignored + or “ ” to search them Search which versus that. Only versus is searched on. Which and that are ignored. To require common words to be searched: +which versus +that ”which versus that” Excluding -word -“phrase in quotes” “acute pancreatitis” diet –cat –dog –“pancreatic cancer”
  34. 34. Basic Searching OR allows more than one term allows pages with at least one of the terms OR requires at least one of the terms joined by it to appear somewhere in the document, in any order. “abdominal pain” OR blacks ear OR nose OR throat The more words you enter connected by OR, the more documents you get. Broadens the search.. USES: o The OR operator is generally used to join similar, equivalent, or synonymous concepts. "global warming" OR "greenhouse effect" Abdomen Pain
  35. 35. Basic Searching AND (default) is the small overlap where both terms occur AND is the default and only needs to be typed if you are using other Boolean operators with ( ). Ex. infopeople training is logically the same as infopeople and training The more words you enter connected by AND, the fewer documents you get. All your words will be searched on USES: o The AND operator is generally used to join different kinds of concepts, different aspects of the question. o "global warming" AND "sea level rise" AND california Abdomen Pain
  36. 36. Basic Searching AND NOT excludes pages that mention PAIN, even if they also mention ABDOMINAL Excludes documents containing whatever follows it. The AND NOT operator is generally used after you have performed a search, looked at the results, and determined that you do not want to see pages containing some word or phrase. USES: • The AND NOT operator should be used with extreme caution, because it eliminates the entire page, and some pages may be of value to you for other information they contain. I almost never use and not for this reason. o "global warming" AND "sea level rise" AND NOT california - The first two terms must be somewhere and any page containing california will be thrown out. Abdomen Pain
  37. 37. Basic Searching NEAR dogs NEAR cats requires both terms, like AND, with the added requirement that they be within 16 words of each other Requires the term following it to occur within a certain proximity of the preceding word in the search. In, NEAR requires the terms to be within 16 words of each other in either direction. Joining words by NEAR gives you fewer documents than AND, because it requires the words to be closer together. USES: o The NEAR operator is used when you want to require that certain terms appear in the same sentence or paragraph of the document. o "global warming" NEAR "sea level rise" - Requires the two phrases to occur within 16 words of each other, in either direction.
  38. 38. Basic Searching ( ) parentheses: "Nesting" Require the terms and operations that occur inside them to be searched first. This is called "nesting." Parentheses MUST BE USED to group terms joined by OR when there is any other Boolean operator in the search. o "global warming" AND "sea level rise" AND (california OR "pacific coast*") - Requires first two terms somewhere in all documents, and either california or pacific coast. • Parentheses also MUST BE USED with NEAR: o ("global warming" NEAR "sea level rise") AND (california OR "pacific coast*") - Requires sea level rise to be within 16 words of global warming; the rest can be anywhere in the pages. The parentheses guarantee that the effect of near stops with sea level rise.
  39. 39. 61 Searching PubMed  Let us use this search: “I was exposed to asbestos for years in school. Can that cause gastrointestinal cancer?”
  40. 40. 62 Entering Your Search Terms  Enter terms: asbestos gastrointestinal cancer
  41. 41. 63 How Does PubMed Interpret What You Type in the Box?  PubMed uses Automatic Term Mapping and maps to:  Medical Subject Headings – medical terms  Phrases  Author Name – lastname initial(s), e.g., smith j, smith ja  Journal Titles – full journal title, MEDLINE abbreviation, ISSN How do you think PubMed searched your terms?
  42. 42. 64 The Details tab The Details tab
  43. 43. 65 When to Limit?  There are many reasons for refining a search strategy. You may want to:  Exclude foreign language titles  Look for articles published within a certain timeframe  Retrieve articles that focus on women or perhaps just children
  44. 44. 66 A quick glance at the results…. Square brackets
  45. 45. 67 The Limits tab Limits tab
  46. 46. 68 Working with Results  Citations display in batches of 20 with most recent additions on top.  Use the check boxes to select multiple citations to view  Click on icons for more information, such as the abstract
  47. 47. 69 A Closer Look at Starting a Search Enter search terms here and then click on Go. Add Limits like date, language, publication type, and more.
  48. 48. 70 Related Articles Related Articles
  49. 49. 71 Links to LinkOut LinkOut
  50. 50. 72 The Clipboard tab  Lets you keep track of the good ones while you are still searching  How to:  #1: Check the citations to keep  #2: Use the Send pull-down menu to select Clipboard  #3:Click on Send.  Will keep up to 500 records for 8 hours!
  51. 51. 73 Are there other ways to limit your search?  Add additional terms to query box  copd air pollution  Use Boolean Connectors  AND, OR, NOT
  52. 52. 74 Combination Searching  Let us use the search: “I am looking for an article from a few years ago (maybe 4-5 years ago) by Dr. Keys about cervical cancer treatment. It was published in the New England Journal of Medicine.”
  53. 53. 75 Combination Searching  PubMed uses Automatic Term Mapping and maps the search terms as:  keys  keys[All Fields]  cervical cancer  "cervix neoplasms" [MeSH Terms]  new england journal of medicine  "N Engl J Med"[Journal]
  54. 54. 76 Advanced Searching  Let us use this search: “My neighbor had a stroke. I understand that Dr. Chin has done research on the neurological aspects of this and it was published in the journal Neurology.”
  55. 55. 77 Preview/Index tab  Preview the number of search results before displaying the citations  Refine searches by adding one or more terms one at a time  Add terms to a strategy from specific search fields
  56. 56. 78 Preview/Index tab
  57. 57. To Know: Value of research What to search How to search
  58. 58. Doing Literature Search