SEARCH ENGINES, REVIEW OF LITERATURE, PUBMED

1. SEARCH ENGINES
(REVIEW LITERATURE)
By:M.Sruthi,1st
yr pg of community medicine
Mentor : Dr.Sudha bala , Assistant professor , ESIC medical
college,Hyderabad

2. OBJECTIVES
 Introduction to search engines
 Identify suitable information sources
 Access main search engines on the web

3. What is a Search Engine?
 It is to extract requested information from the huge database of
resources available on the internet.
 It is for finding the required information without knowing where exactly
it is stored.
 Internet usage has been increased in recent days with the easy to use
search engines like Google, Bing and Yahoo!

4. Appropriate place to search
•
PubMed/Scopus/Goo
gle Scholar database
etc
• Free open Access
• Fee Based – From Libraries
• HON certified sites
• Web Search
Engines-Google
• Cochrane Library
• Map of Medicine
Systematic
reviews/Meta –
analysis/EBMS
CochraneLibrary
Map of Medicine
General Info
Specific query
PubMed/
Scopus/Google
Scolar database
etc
Archived full text
articles
Free open Access
Fee Based – From
Libraries

5. Different Types of Search
Engines
 Search engines are classified into the following
three categories based on how it works.
1. Crawler based search engines
2. Human powered directories
3. Hybrid search engines

6. Why searching a literature?
 Staying current with advances in medicine
 Identifying information and ideas
 Increasing breadth of knowledge
 Putting our work into perspective
 Carrying on from where others have already reached

7. Why perform literature review?
 Saves ourself from work!
 Know the subject matter better
 Suggest new research topics, questions and methods

8. How to conduct literature review :
 The first step is to identify broad keywords relevant to our subject
 These keywords used by search engines to construct and index their archived references,
enabling us to access vast information online.
 Later on these keywords can be expanded to refine the search into specific subheadings and
enable us to structure our review
 It is essential to read the entire article so that we can assess the evidence and summarise the
findings in our own words.

9. How to write a literature review
 start with a brief introduction,
 followed by the text broken up into subsections
 conclude with a summary to bring everything together.
 A summary table including title, author, publication date
 key findings is a useful feature to present in your review
 We should group similar findings and comment on differences in results or study
outcomes. This may be due to differences in subjects, experimental materials,
methodology or how the data were analysed.

10. Literature review: Organized search
Organize information relate it to the research question
Synthesise results : summary of what is known and not known
Identify lacunae as appears in the literature
Develop questions for further research

11. Introduction to literature search
 Websites
 Search engines
 Databases
 Know your resources – map them to your needs
 Know the principles of searching
STEP BY STEP APPROACH

12. MAPPING NEEDS TO RESOURCES
 Needs : Simple to complex
 What is wilsons disease
 What are the current advances in the treatment of cerebral malaria
 Which is more effective for severe malaria – Artesunate or Quinine`
Dictionaries,
encyclopideas,
textbooks,
Handbooks,manuals
Journals,
Thesis,
conferences,
Clinical
trials,
registries
Evidence
from
systemic
review
Guideline
s to be
followed
when
treating
patients
Summarie
s: Quick
referener
esource/
Recall
resource

13. EXAMPLES
 http://WWW.harrisonism.com/
Website of Harrison’s Principles of internal Medicine
Text book – Type I resources
http://www.pubmed.gov
Website of Pubmed – a resource for journal articles
journal articles- Type II resources
http://www.cochranelibrary.com/
Website of the Cochrane library
 Systematic reviews – Type III resources
 Other Bibliographic databases –Type II resources
- Mix of Type II & Type III resources

14. EXAMPLES:
 http;//www.clinicalkey.com/
Website of “Clinical Key’’
Mix of Types I & II & III
 Books , Drug Monographs
 Journals
 Guidelines , Procedure Consults

15. INTRODUCTION TO PUBMED
 What is Pubmed?
It is an INDEX to articles published
It has around 5000 articles
It has English and other languages

16. What does an index mean?
 An index means it contains “ bibliographic details “ of
articles ( in the journals)
- Author
- Title
- Journal details ( issue no, volume no, page no)
- Abstracts…..

17. PUBMED
 Pub Med – the data base – does NOT contain the full
text of articles
 It may link a bibliographic record to the full text on
the journal website
 The article being free or not on the jouranls website
it is publishers decision

18. PUBMED
 The Pub med database is compiled in the National Library of
Medicine, USA
 For every journal selected for inclusion on PubMed , the Editor has
to
 Send every issue to the NLM
 Provide full text access of articles to the NLM
 It includes books of medical sciences but not clinical ones
 PubMed comprise more than 27 million citations

19. What is medline ?
 It was the original database compiled by the National Library of
Medicine before it was hosted on the internet
 It first started as a print resource called the Index Medicus and when
computerized catalogue started it became a computerized resource
called MEDLINE
 It used to be available only on subscription online later dispatched to
libraries as CDs
 It has descriptive keywords or tags

20. PUBMED CENTRAL
 It is called an archive
 It is a place where full articles are deposited
 It is not an index to an journal but full text archives
of different journals

21. FOUR PRINCIPLES OF SEARCHING
 Principle I : Word search
 Principle II: MeSH search
 Principle III : Field search
 Principle IV: Boolean operators

22. Principle I ( Word search )
 When we search for a term, PubMed looks for records that contain our
search term
 This search term contains in the bibliographic details & Abstract
 The PubMed search engine does not go out of the web and search the
full text
 The full text is not in the PubMed database it’s in the journal website

23. Principle II : MeSH search
 MeSH terms are used to describe the article
 If we click on MeSH terms we will get tags
 If there are star on the terms that means they are explained more detailly
 Standardized , specific keywords are tagged to most PubMed records

24. Principle II : MeSH search

25. WHAT IS MESH
 Medical Subject Headings
 MeSH terms : A collection of standard terms
 MeSH terms are from THESAUSRUS specifically the mesh thesaurus
 Terms from this collection are used to tag or describe every article record
 Tagging done by : Professional “ Indexers “ in the NLM

26. HOW DO WE SEARCH USING MESH TERMS
 Search for records that contain the word bronchiolitis
 This word must contains in the list of MeSH terms
How can we instruct PubMed to do that?

27. TYPES OF MESH SEARCHES
 Bronchiolitis[mesh] 42336
 Bronchiolitis/etiology[mesh] 22430
 Bronchiolitis[major] 33571
 Bronchiolitis /etiology[major] 12284

28. Principle III ( Field search )
 We can search for our terms
(word or number) in other
fields /areas of a Bibliographic
record

29. FIELD – SEARCH “ CHEST “
 Chest[TI] Title
 Chest[tiab] Title or abstract or both cases
 Chest[Jour] Journal title
If we search as We will find our term in the

30. FIELD SEARCH
 Chest[Au] Author
 Chest[AD] Author’s address
 Chest[MeSH] List of Mesh terms
 Chest ALL AREAS (except the full
text)
143[page] Page number
2016[pdat] Date/year
If you search as You will find your term in the

31. FIELD – SEARCH

32. Principle IV (Using Boolean Operators)
 Combining for more than one search term
HOW DO WE COMBINE SEARCH TERMS ?
We want to find records in PubMed
 About both asthma as well as bronchitis
 Articles by White in Thorax in 2015

33. WRONG METHODS
 Prevalence of Asthma and Bronchitis in India
 Underlined the prepositions or conjunctions they are
completely ignored by the pubmed
RIGHT METHODS
Combine search terms with
AND
OR
NOT
All in capitals
These are
called Boolean
operators

34. BOOLEAN OPERATORS
Asthma
Asthma AND
Bronchitis
Asthma OR
Bronchitis
Asthma NOT
Bronchitis
Results :
100
Results : < / = 100
Results : > / = 100
Every record contains
a minimum one term
Results : < 100
They will contain
Asthma not
Bronchitis

35. Records containg
Asthma
10
Records
containing
Bronchitis
7
4
Asthma and
Bronchitis

36. Records
containing
Asthma
10
Records
containing
Bronchtis
7
4
10 + 7 – 4 = 13
Asthma OR Bronchitis

37. ASTHMA NOT BRONCHITIS
4
Records
containing
Asthma
10
Records
containing
Bronchitis
7

38. SEARCHING WITH MESH

39. SEARCHING WITH MESH

40. SEARCHING WITH MESH

41. SEARCHING WITH MESH

42. SEARCHING WITH TWO TERMS

43. HOW DO WE USE SUBHEADINGS

44. Searching pubmed with MeSH – Advanced
Example :
Obesity as a cause of back pain

45. Using filters
 How does a filter work
• Based on a Boolean operator
 More filters – first display – then apply
 Note the Boolean operators

46. Display format
 Different display formats
 Sort options
 Number per page

47. Saving search strategies
 Send to options
 File ( six options )
o MEDLINE option useful for exporting to reference managers
• Collections – permanent storage
• Email
• Clipboard

48. Single citation matcher
INCOMPLETE REFERENCE
Kumar v . et al . Forecasting malaria … 2014

49. Single citation matcher

50. Journals in NCBI Databases
 We can find a journal by
 Title
 MeSH Terms – eg Tuberculosis
 Broad subjects terms – eg Pediatrics
 Abbreviations – eg Indian J Tuberc
We can find a detailed information about journals
We can find the journal abbreviation by searching for the title or vice versa

51. Journals in NCBI Databases

52. Journals in NCBI Websites

53. Journals in NCBI websites

54. Finding free full texts of articles
 Literature search is a first step to identify what has been published
 Second step is to find free article
While searching PubMed
 Filter – Free full text
 For the rest
 Some are free for short durations ( even if not marked free )
 Some foreign journals are free in India
 In their case , just click icon and try

55. Finding free full text of articles
 Paste the article title in Google scholar. We may find the article in :
 The authors institutional archive
 Research Gate ( requires free registration to use )

56. While searching PubMed
 If not free, try emailing the author – find the address in the address area
 Several Indian / developing country articles are not marked free ; go to the journal
website and check for the article
 MedInd is a national informatic center of India ( NIC) .In this website they host several
journals
 MedInd is a full text website

57. Finding an article through libraries
 Go to NUCSSI – http://nucssi.niscair.res.in
 On the right side of the screen look for the search box
 Choose the journal option
 Type in the journal option
 Type in the journal title and pick the Right option
 We will know which library in the country has the journal
 Ask your librarian to get it from the library

58. Finding an article through libraries
 Go to the CSIR Gateway
 Type in the name of the journal in the search box
 There is an option – RA – to request the article
 Make a request , or take librarians help to ask for the article
Check the Qmed website page for more details
http://www.qmed.ngo/full-text-articles/

59. Advanced Search page

60. Another source of information is searchable
online reference databases
 MalaCards
 Reactome
 MalaCards,the human disease database that integrates a wealth of
clinical information with data on clinical trials, molecular bases of
disease and experimental resources from other reference databases
and published research.
 Online pathway tools, such as Reactome, can also be used to access
collective knowledge of molecular interactions with disease

61. COCHRANE LIBRARY
 Collection of evidence based medicine databases
 Cochrane databse of systematic review(CDSR)
 Cochrane central register of controlled trials(CENTRAL)
 Database of abstracts of reviews of effects(DARE)
 Health technology assessment database(HTA)
 NHS Economic Database(EED)

62. Google scholar
 It is launched in 2004
 It will not get to the full text of every search result
 Older results appear first, It returns the most relevant
results first
 It automatically calculates and displays the total citation
count, h-index and i10-index

63. ELSEVIER
 It is a Dutch Academic publishing Company specialising in scientific,
technical and medical content
 It published more than 600000 articles annually in over
2700 journals and 40000 e books

64. SHODHGANGA
 Shodhgnagaa is an open access of Indian Theses & Dissertation
 It is maintained by INFLIBNET centre
 The INFLIBNET centre is also maintaining another repository – Shodhgangotri which is a repository
of the synopsis and research proposals of the PhD programmes in Indian university
 It is a collection of 3880 thesis
 71 Universities are signed
 62 Universities started contribution

65. Take home messages
 A literature review should set the scene, demonstrate current knowledge, identify gaps in the field and, if
relevant, demonstrate where your research fits.
 It should be a personal critical appraisal of the current knowledge in a subject area.
 It should be evidence-based, using a variety of peer-reviewed original research articles, reporting facts,
commenting on similarities or discrepancies and highlighting knowledge gaps or areas of unmet need.
 Structure your review with an introduction, subsections and a summary table.
 Summarise information in your own words and give appropriate credit to other authors’ work.
 A systematic approach to writing a literature review should be used to reduce bias.