For Lexis this is within approximately 75 words of each other rather than actual paragraph. Used to search for two words within the same paragraph. For Westlaw the two words are actually within the same sentence. Dog /s cat = Dog is in the same sentence (or 25 words) of cat. For Lexis this is within approximately 25 words of each other rather than actual sentence. Used to search for two words within the same sentence. For instance, dog /5 cat will search for documents where the word dog appears within 5 words of cat. Used to search within a particular number the word. The farther the distance between the words, the more likely you will get results.īut the nearer the words, the more likely the concepts the words represent are related to each other. However, if you are not getting enough documents that way, you may want to spread the search farther apart, to look for the two words within the same sentence, or maybe the same paragraph. For instance if you are looking for documents that talk about officers of the court, you may want to have the word officer be very close to the word court. Generally the closer the words are together the more related the concepts will be. If you don't put in the parentheses, the search statement is processed strictly from left to right, so that the AND is done first. This search strategy will retrieve records containing both of the concepts, Diet Therapy + Bulimia, or any records with the concept Anorexia.Sometimes you may want to have two words be near each other. For example, diet therapy AND ( bulimia OR anorexia ) will retrieve records containing the two concepts, Bulimia + Diet Therapy, or the two concepts, Anorexia + Diet Therapy, or records that contain all three concepts, Bulimia + Diet Therapy + Anorexia. Searches within parentheses are performed first and operations proceed from left to right. The order in which the operations (AND, OR, NOT) are processed can vary between systems. Use parentheses ( ) to separate keywords when you are using more than one operator and three or more keywords. Nesting, or mixing the Boolean operators, is a way to combine several search statements into one comprehensive search statement. For example, you could search multi-infarct dementia by using Dementia NOT Alzheimer's.īut be careful using this because you would eliminate records discussing both types of dementia, as all articles discussing Alzheimer's are eliminated. The final Boolean operator NOT allows you to exclude concepts not relevant to your search. The more concepts or keywords you OR together, the more records you will retrieve. For example, kidney disease OR renal diseases will retrieve citations using either (or both) terms. This expands your search by retrieving citations in which either or both terms appear. The Boolean operator OR allows you to broaden a concept and include synonyms. The more concepts you AND together, the fewer records you will retrieve. For example: "Does taking aspirin cause Reye's Syndrome in children?" This will retrieve citations that discuss all three concepts in each article. When terms/concepts are combined with the AND operator, retrieved records must contain all the terms. (The shading represents the outcome of the Boolean operation.) The circle diagrams that help illustrate the relationships between the sets used in Boolean logic were named after another mathematician, John Venn.
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