Adding quotations keeps all the words together so they are searched as terms and not as individual words.
You may be used to typing a question or sentence directly in the search box--like with Google. In search tools, like the library catalog or databases, this type of searching will not work. Typing a sentence or question will result in many erroneous, irrelevant, or unacceptable results
For database searching, use keywords along with specialized search words called Boolean operators.
The terms AND, OR, and NOT are used to either narrow or broaden your results. Boolean terms are always in all uppercase letters to distinguish them from the keywords.
Every term connected with an AND will be found in the results of the search tool.
In creating an AND search statement, you will not want to use every term you have identified. Doing so will produce a small number of results or no results at all. A better approach is to select terms for each separate concept in your research question, and then connect them with an AND. Try two or three of your strongest keywords linked together at a time.
Remember, every time you add a word you will narrow your search and receive fewer results. If you have too few results, eliminate keywords or substitute others.
With OR, you are telling the search tool that you want information about either one idea or another. This is an ideal search strategy to use with synonyms. This can be particularly effective when combined with an AND term.
Here you are directing the search tool to ignore results including a particular word or phrase. This is helpful to eliminate topics that change the results.
For example, if you want to know about childhood obesity from around the world, but not childhood obesity in the United States, you can search for "Childhood obesity" NOT "United States" to eliminate any results that mention the United States.
NOT can be used in conjunction with AND or OR. Just make sure NOT is listed after the keyword you want to include and before the keyword you want to be excluded.
*Some search tools use a minus sign (-) instead of NOT to eliminate keywords