Boolean searching is defined by the use of its terms and connectors. Some of the most important words for Boolean searching are the connectors AND, OR, and NOT. Using these three terms to connect various search terms helps the search engine target what is truly important to the researcher. Other valuable connectors are proximity connectors like /s, /p, and w/# and truncation/wildcard symbols like !, *, # and ?. Each system varies, so be sure to check the HELP or SEARCH FAQS of the individual database you use.
You can revisit the Advanced Search Cheat Sheets below for reminders on Boolean connectors and how each of the major databases use them.
Aside from using terms and connectors searching another useful search tool is the advanced search function available on most websites.
Advanced search helps narrow searches and occasionally offers reminders on the terms and connectors that a given search engine uses. Most databases, websites, and research tools have an advanced search option, often found near the search bar.
Advanced search can help you refine your search. For example, here is Google's advanced search page:
See how Google prompts you to think about the relationships between your search terms in the first part of its advanced search page. Further down the page, Google encourages you to narrow your results to certain websites, languages, etc. The end result is a much more targeted search that should be more useful for the researcher. (For example, it can be very useful to restrict to search to a certain type of site like .gov. It can also be useful to search a website that isn't retrieving the results you are looking for. I find it a lot easier to search for articles from say, the New York Times, via Google than directly through the NYTimes.com page).
More targeted research engines make even better use of the Advanced Search page. Look at this screengrab from Westlaw:
You’ll see that in addition to greater specificity of search terms you’ll get the added functionality of running a search exclusively within certain parts of the document you’re looking for. This is called “Field and Segment Searching.” Here you can enter terms and ask Westlaw or Lexis to find only hits that have a certain term within certain fields or segments of a legal document. As a helpful tip, the fields and segments change depending on the type of legal document you’re looking at. To get the most out of this type of advanced searching, be sure to narrow your search just to a specific type of legal document that best fits your search needs (i.e. cases, statutes, regs, etc.).
And here are resources for using these operators by preferred search engine: