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© 2006 1 Literature searching A literature search identifies relevant information sources that are used to answer clinical questions.

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Presentation on theme: "© 2006 1 Literature searching A literature search identifies relevant information sources that are used to answer clinical questions."— Presentation transcript:

1 © 2006 1 Literature searching A literature search identifies relevant information sources that are used to answer clinical questions

2 © 2006 Evidence-based Chiropractic 2 PubMed searching Search using keywords, text words, or subject headings –PubMed looks for entered keywords or text words in each of the possible fields of a record –e.g., author, title, abstract, journal name, volume, issue, date, etc.

3 © 2006 Evidence-based Chiropractic 3 Features bar Query box Sidebar Search dropdown list

4 © 2006 Evidence-based Chiropractic 4 Search terms are typed into the Query box The Search drop-down list is typically left in its default position The MeSH database can be searched from the Search drop-down list or using a link in the sidebar PubMed homepage Headache

5 © 2006 Evidence-based Chiropractic 5 PubMed sidebar The tutorial is excellent Link to the MeSH Database Clinical Queries link

6 © 2006 Evidence-based Chiropractic 6 The Clinical Queries link permits searches designed to answer clinical questions –Topics can be searched by clinical study categories (e.g., therapy, diagnosis, prognosis, etc.) –Or to only search for systematic reviews PubMed sidebar (cont.)

7 © 2006 Evidence-based Chiropractic 7 PubMed Clinical Queries search Select study category Search term

8 © 2006 Evidence-based Chiropractic 8 The MANTIS High Clinical Relevancy option is similar to PubMed’s Clinical Queries High Clinical Relevancy limits a search to articles that involve clinical trials or case reports MANTIS

9 © 2006 Evidence-based Chiropractic 9 MANTIS advanced search page Search term High Clinical Relevancy check box MANTIS Advanced search screen

10 © 2006 Evidence-based Chiropractic 10 PubMed Basic Search mode Simply enter search terms in the Query box and click Go PubMed produces a list of retrieved citations Stopwords are ignored by PubMed –e.g., the, and, because, thus, etc. –They don’t add or detract anything from the search results

11 © 2006 Evidence-based Chiropractic 11 Search results for chiropractic Click to see full citation Check box then click Display

12 © 2006 Evidence-based Chiropractic 12 Select format for display view Sort records by option Results can be sent

13 © 2006 Evidence-based Chiropractic 13 Multiple checkboxes More than one record can be viewed at the same time by selecting the checkboxes next to the desired citations –Select a drop-down menu choice to set the display format PubMed keeps track of checkboxes and displays all checked records when requested by clicking Display

14 © 2006 Evidence-based Chiropractic 14 Advanced PubMed search tactics Limits –Click the Limits tab on the Features bar Select the limiting search criteria from the screen that appears

15 © 2006 Evidence-based Chiropractic 15

16 © 2006 Evidence-based Chiropractic 16 More limit criteria

17 © 2006 Evidence-based Chiropractic 17 Limits (cont.) Searching with limits will only retrieve articles that meet the limiting criteria that are set Selecting from the Type of article menu limits searches to specific publication types –e.g., meta-analyses, clinical trials, case reports, editorials, etc.

18 © 2006 Evidence-based Chiropractic 18 Limits example A search using the terms carpal tunnel syndrome without limits yields 5,728 citations―far too many to contend with Whereas only 15 are retrieved when the following limits are set –English –Clinical Trial –Complementary Medicine

19 © 2006 Evidence-based Chiropractic 19 Field tags Used to refine searches by forcing the query to consider specific search fields Results are very similar to what is achieved using Limits –Thus, field tags are optional in PubMed –Some think field tags are easier to use and prefer them Limits function is only partial in MANTIS

20 © 2006 Evidence-based Chiropractic 20 Field tags (cont.) Field tags are placed within brackets after search terms –Does not matter how many spaces between the search term and the field tag –Does not matter whether upper or lower case letters are used To use field tags –Enter the search term in the query box followed by a field tag within brackets

21 © 2006 Evidence-based Chiropractic 21 Common PubMed Field Tags Affiliation [AD] Author Name [AU] Journal Title Abbreviation [TA] Language [LA] MeSH Terms [MH] Publication Date [DP] Page Number [PG] Publication Type [PT] Volume [VI] Issue [IP] Subset [SB] Text Words [TW] Title Words [TI]

22 © 2006 Evidence-based Chiropractic 22 Field tags example If spinal stenosis is searched for in PubMed –Without any field tags, 2960 citations result spinal stenosis –Using the Title Words [TI] field tag, only 731 spinal stenosis [TI] –Combined with Author Name [AU], only 4 spinal stenosis [TI] smith [AU]

23 © 2006 Evidence-based Chiropractic 23 Boolean (Logical) operators Words that combine search terms to narrow down or broaden searches Consist of AND, OR, and NOT –Should always be capitalized Used by many databases, including PubMed and MANTIS

24 © 2006 Evidence-based Chiropractic 24 Boolean operator AND AND limits or narrows down a search Combines terms so that only citations that contain both terms are retrieved For example –A PubMed search for sacroiliac joint yields 2,760 citations and manipulation 33,819 –Searching sacroiliac joint AND manipulation narrows the results down to 76

25 © 2006 Evidence-based Chiropractic 25 sacroiliac joint 2,760 citations manipulation 33,819 citations AND example sacroiliac joint AND manipulation 76 citations

26 © 2006 Evidence-based Chiropractic 26 Combining more than 2 terms sacroiliac joint AND manipulation AND chiropractic 18 citations sacroiliac manipulation joint chiropractic

27 © 2006 Evidence-based Chiropractic 27 Boolean operator OR OR expands a search –All articles that contain either of the queried terms are retrieved For example –Searching PubMed for sacroiliac joint OR manipulation expands the results to 36,503 OR is useful when searching for different versions of a word –e.g., manipulation OR adjustment

28 © 2006 Evidence-based Chiropractic 28 OR example sacroiliac joint 2,760 citations manipulation 33,819 citations sacroiliac joint OR manipulation 36,503 citations

29 © 2006 Evidence-based Chiropractic 29 Boolean operator NOT NOT also limits or narrows down a search –Only retrieves citations that do include the first term, but do not include the second term For example –Searching PubMed for sacroiliac joint NOT manipulation narrows down the number of citations from 2,760 to 2,684 –76 articles include manipulation and the SI joint, so they are eliminated

30 © 2006 Evidence-based Chiropractic 30 NOT example sacroiliac manipulation joint sacroiliac joint NOT manipulation Articles that include both sacroiliac joint and manipulation are eliminated

31 © 2006 Evidence-based Chiropractic 31 Nesting Controls the order in which PubMed processes search terms –From left to right by default Search terms are enclosed in parentheses –Terms within the parentheses are processed first –Boolean operators can be included

32 © 2006 Evidence-based Chiropractic 32 Nesting example If a doctor wants information on the non- surgical treatment of carpal tunnel syndrome, the query might look like this –carpal tunnel syndrome AND (treatment NOT surgery) This search will locate articles that deal with treatment, but not those that involve surgery

33 © 2006 Evidence-based Chiropractic 33 Nesting example 2 Searching chiropractic AND (whiplash OR chronic pain) The database will first find all references that contain whiplash plus those that contain chronic pain Then it will restrict results to those that also contain the word chiropractic

34 © 2006 Evidence-based Chiropractic 34 The AND operator is used between words by default PubMed searches for headache AND therapy exactly the same way as headache therapy –Thus, AND is sometimes optional To see how PubMed performed a search –Click the Details tab after the search is complete –Read the Query Translation

35 © 2006 Evidence-based Chiropractic 35 Details tab Translation is exactly the same when AND is used

36 © 2006 Evidence-based Chiropractic 36 Query Translation Useful in figuring out why an unproductive search failed Also to plan a subsequent search strategy that will be more successful

37 © 2006 Evidence-based Chiropractic 37 Automatic Term Mapping When terms are searched without a field tag, they are matched (in order) against the –MeSH Translation Table –Journals Translation Table –Full Author Translation Table –Author Index

38 © 2006 Evidence-based Chiropractic 38 Automatic Term Mapping (cont.) If the term matches a MeSH term, it is searched both as a MeSH term and a Text Word The Journals Translation Table yields an abbreviated title when the journal’s full title is searched –Journal of the American Medical Association –JAMA or J Am Med Assoc

39 © 2006 Evidence-based Chiropractic 39 Automatic Term Mapping (cont.) The Full Author Translation Table retrieves the author’s full name –Only for articles published after 2001 Order of names doesn’t matter –Searching meeker william c is equivalent to william c meeker Commas are not necessary –Helpful to distinguish first from last names (e.g., John James)

40 © 2006 Evidence-based Chiropractic 40 Truncation (a.k.a, wildcard search) Search for various uses of the same root word –The root word verte can be expanded to vertebra, vertebrae, vertebral, etc. –Searching only vertebral misses other forms of the word The root word with an asterisk retrieves all forms of the word –e.g., verte*

41 © 2006 Evidence-based Chiropractic 41 Truncation (cont.) An * can be placed at the beginning or end of search terms An * can also be placed within a word when a letter is variable or absent –The search term an*emia will look for anemia and anaemia –analy*e will look for analyze and analyse

42 © 2006 Evidence-based Chiropractic 42 Phrase searching Forces PubMed to search for a phrase rather than individual terms Only the exact phrase will be queried The phrase must be place within quotation marks –A search of intervertebral disc herniation produces 11,747 citations –Whereas “intervertebral disc herniation” produces only 183

43 © 2006 Evidence-based Chiropractic 43 Medical Subject Headings (MeSH) A list of vocabulary terms used to index medical literature –Developed by the National Library of Medicine (NLM) MeSH terms are assigned to all MEDLINE records by NLM indexers corresponding to the article’s major topics

44 © 2006 Evidence-based Chiropractic 44 Finding MeSH terms Select MeSH from the drop-down list next to the Search button on the PubMed homepage Enter term in PubMed query box A list of the MeSH terms or alternative suggestions will appear

45 © 2006 Evidence-based Chiropractic 45 Select MeSH Enter term

46 © 2006 Evidence-based Chiropractic 46 No terms found Suggested terms Click likely terms

47 © 2006 Evidence-based Chiropractic 47 List of MeSH terms (only one in this case)

48 © 2006 Evidence-based Chiropractic 48 Finding MeSH terms (cont.) Another way to find MeSH terms is to view the citation format of an article –Click Citation from the drop-down list next to the Display button located at the top and bottom of each page of retrieved records

49 © 2006 Evidence-based Chiropractic 49 Check the articles of interest Select Citation

50 © 2006 Evidence-based Chiropractic 50 The complete citation appears Including a list of MeSH terms

51 © 2006 Evidence-based Chiropractic 51 Finding MeSH terms (cont.) A final way to find MeSH terms is to perform a free-text search then look at PubMed’s automatic term mapping translation –Click the Details tab and look at the terms in the Query Translation box –MeSH terms have a [MeSH Terms] field tag next to them

52 © 2006 Evidence-based Chiropractic 52 Building a MeSH search From the MeSH database –Select terms to include in the search by checking the adjacent box –Select the location to send the term to in the Send to drop down list –Other MeSH terms can be found and added to the Search Box by repeating this process

53 © 2006 Evidence-based Chiropractic 53 Check MeSH term Send term to Search Box with AND, OR, or NOT

54 © 2006 Evidence-based Chiropractic 54 More terms can be added to build a search Click when ready to perform the search

55 © 2006 Evidence-based Chiropractic 55 MeSH (cont.) MeSH indexers must –Have at least a bachelor's degree in a biomedical science –Have reading knowledge of one or more foreign languages –Be trained in principles of MEDLINE indexing and complete several weeks of on-the-job training at the Library MeSH terms may at times be incorrect

56 © 2006 Evidence-based Chiropractic 56 MeSH terms are optional Search using any word in the title, abstract, or other field of the citation However, searching with MeSH terms narrows down the search and provides more focused results MeSH terms should be used when possible

57 © 2006 Evidence-based Chiropractic 57 MANTIS - Controlled Supplemental Vocabulary Similar to MeSH headings –Functions with MeSH terms –Search terms are specific to complementary and alternative medicine –e.g., Gonstead Technic, Toggle Recoil Adjustment, Innate Intelligence, etc.

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