Introduction to Database Searching - Vanderbilt University Medical.ppt
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1、Introduction to Searching Bibliographic Databases,Jennifer Lyon, M.S., M.L.I.S. Eskind Biomedical Library Vanderbilt University Medical Center Nashville, TN,Some Reasons for Searching the Medical Literature,To answer a specific patient case-related question (practice) To learn more about a medical t
2、opic (education) To determine current best practice (guideline) To give the best possible care to patients using evidence-based medicine,Information Overload,PubMed (Medline) contains over 18 million journal citations going back to 1950,*statistics from http:/www.nlm.nih.gov/bsd/bsd_key.html,Techniq
3、ues for Improved Searching,Ability to structure and parse a question Knowledge of basic database structure Use of Boolean Logic Use of Field Searching Use of Controlled Vocabulary Specialty techniques (truncation, etc.) Consistent step-by-step procedure,Asking the Question: PICO,Patient, Population
4、or Problem What are the characteristics of the patient or population? What is the condition or disease you are interested in? Intervention or exposure What do you want to do with this patient (e.g. treat, diagnose, observe)? Comparison What is the alternative to the intervention (e.g. placebo, diffe
5、rent drug, surgery)? Outcome What are the relevant outcomes (e.g. morbidity, death, complications)?,http:/healthlinks.washington.edu/ebp/pico.html,Parsing the Question,What are the main concepts in your question? Sample question: Does nutrition therapy improve decubitus (pressure) ulcer healing in a
6、n elderly patient? Concepts:,Nutrition therapy,Decubitus/pressure ulcers,Ulcer healing,Elderly patients,Treatment efficacy,A database is an organized collection of data. Bibliographic databases are searched through many of the same techniques as any other database Focus will be on PubMed, but these
7、techniques apply to ANY literature database,Examples of Records and Fields,Examples of Records and Fields,RED=RECORD BLUE=FIELD PURPLE = ONE PIECE OF DATA,Searching a Database,Different search interfaces do the same things in slightly different ways Good search interfaces should provide Ability to s
8、earch for a specific item Ability to search for related items to a known item Ability to search in a specific field or fields Ability to combine search terms using Boolean Logic Ability to retrieve search results in a useful way,Boolean Logic,A British mathematician named George Boole (1815-1864) de
9、veloped an algebraic system of logic that is now widely used in computer and electronic systems including database searching. While Booles algebraic system can be complex, a very simple form of Boolean Logic is used for searching most bibliographic databases.,Boolean Operators,Standard Boolean Logic
10、 for database searching uses 3 relationships among search terms. AND OR NOT It is both simple and powerful.,AND,BOTH terms included in any results. If a record has only one of the two terms, it will not be retrieved. If the record has neither term, it will not be retrieved. What does this do to the
11、amount of records retrieved?,OR,Only one (NOT both) of the terms are in the results OR will retrieve the record if both are included. What does OR do to the amount of records retrieved?,NOT,Excludes any results containing the term Records containing both will not be retrieved. What does NOT do to th
12、e amount of records retrieved?,Using OR,“OR” groupings contain terms for the same idea/concept and are usually put in parenthesis (term OR term OR term) where all terms are difference ways of representing the same concept (faculty OR teachers OR professors) (students OR learners OR pupils),Using AND
13、,“AND” groupings contain terms for different ideas/concepts and can combine OR groupings Term AND (Term OR Term) where each represents a different concept heart attack AND smoking Diabetes AND exercise Cancer AND (treatment OR therapy),Using NOT,“NOT” statements are usually put last and can contain
14、an “OR” grouping; they are often used to get rid of a common subgroup Students NOT dental Diabetes NOT juvenile,Putting Them Together,Identify the concepts (Parse the question) List specific terms for each concept Put the terms for each concept in an OR statements within parentheses Combine OR state
15、ments with AND Add any NOT statements to the end,Creating a Boolean Search,QUESTION: Is Vitamin C helpful in treating the flu? Identify concepts and list terms,Step 2,2. Make your OR statements, one per concept (influenza OR flu OR orthomyxovirus) (vitamin C OR ascorbic acid OR ascorbate) (treatment
16、 OR therapy OR management) (outcome OR recovery OR success),Steps 3 and 4,3. Put “AND” between each of the OR statements (influenza OR flu) AND (vitamin C OR ascorbic acid OR orange juice) AND (treatment OR therapy OR management) AND (outcome OR recovery OR success) 4. Consider any NOT statements yo
17、u might want to add. Note: NOT isnt used very often,Parsing a Boolean Search,(emergency OR acute OR critical) AND (treatment OR therapy OR management OR care) AND (motor vehicle accident OR car crash) NOT (pedestrian OR walking) What are the four concepts? What terms are used for each concept? Which
18、 three concepts must be included in all records found? Which concept must not be included in any record found?,Beyond Basic Boolean,Field Searching Controlled Vocabulary Subject vs. Keyword Searching Specialty Features Truncation Phrase searching,Field Searching,Almost all databases will provide you
19、 with some ability to search a specific field or fields. Allows faster searching Allows more accurate searching Not all databases may make all fields searchable. Each search system will require a specific format.,All Field vs. Specific Field Searches,I would like to find articles by John Smith. Sear
20、ch all fields: John Smith Search Author Field only: John Smith I would like to find an article published in 1997. Search all fields: 1997 Search Publication Date Field: 1997 Why waste time searching for a date in the author field or an author in the volume field?,Formats for Field Searching,Differen
21、t databases provide different formats for specifying fields. Most use field names or nicknames Field tags OR labels which may follow a period or be placed in brackets or parentheses. Some databases offer forms or drop-down menus.,PubMed Field tags go in and follow term Field tags can be used within
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