There are three Boolean Operators: AND: All keywords must appear in your results. Using a Boolean Operator will tell the database to connect the terms together in your search. ![]() In this example from the Web of Science database, you can use the Basic search form to add multiple search lines by clicking on Add Another Field. Boolean Operators To search multiple keywords at once, you need to use connector terms, also called Boolean Operators. Sometimes you will have to access the Advanced Search for these options. Take care if using multiple operators as they are processed in the following order of precedence: OR, AND, AND NOT. Many databases offer the functionality to separate out your search terms, and this saves you having to add the parentheses. Boolean searching is available choose from the drop down boxes when search fields are added, or type in the operators ( AND, OR, AND NOT ). AND, OR, and NOT are the primary operators of Boolean logic. OR human as a secondary search - This means that your search results containing human would not be linked in any way to cloning. Simply speaking, a Boolean search is an expression that results in a value of either TRUE or FALSE (in our world, that an article matches the search term (s) or doesn’t). ![]() If you do not use the parentheses and search using the following:Ĭloning AND sheep OR human, your search will be processed as: If you want to find information on cloning humans and cloning sheep, use the following instruction:Ĭloning AND (sheep OR human) - This will search for cloning AND sheep as well as cloning AND human Use the asterisk wildcard character () to include alternative forms of wo rds, plurals. If you use a combination of AND and OR operators in one search, use parentheses (brackets) to group the OR words together so that your search is processed correctly. Boolean Operators are specific words used to combine concepts or keywords to improve the chances of finding relevant information. In Boolean search mode words are searched exactly as they are typed. ![]() They typically recognise AND as the primary operator and will connect concepts with AND together first. Databases usually process the Boolean operators in a logical order.
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