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. Start searching for tweets, articles, titles, and bios with some suggested searches: Companies or Topics (e.g. We’ve compiled this guide to help you make the most of your search. 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. Boolean search query makes it simple to find people, tweets, or articles that mention any name, keyword, company, hashtag, etc. 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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