Basic searching should be sufficient to find material that you want. This page is just you let you know that more advanced searching techniques exist.
Some search engine, like Google, have advanced search pages, but they are not well advertised (Google's advanced search is under the Settings button) and don't offer much that won't be described on the Internet Searching page. Here's Google's advanced search page:
Most of these options are available through the basic search.
Most resources have an advanced search option, which allow you to further limit and refine your search using more filters (the more common filters described on the basic searching page). The distinguishing feature of advanced searching however is the use of Boolean operators
Boolean operators, named after George Boole, a nineteenth century professor of mathematics at University College Cork, are simple words used to combine or exclude keywords in a search
Boolean Operators are simple but complicated. Here's the most common three and what they are used for:
| AND | OR | NOT |
|---|---|---|
| Used to narrow searches | Use to broaden searches | Use to exclude keywords from searches |
| Reduces the number of results |
Increases the number of results |
Reduces the number of results |
| Each result contains all search terms | Each result contains any search term | Each result does not contain the [not] term |
| Football and hurling | Football or hurling | Football not hurling |
|
Results will contain: articles that mention both football and hurling |
Results will contain: articles that mention football only articles that mention hurling only articles that mention football and hurling |
Results will contain: articles that mention football only |
The OR operator is good for combining similar terms when you want to search for related concepts - for example
artificial intelligence OR expert systems OR machine learning
The AND operator is good for combining concepts when you have a specific search in mind - for example
artificial intelligence AND ethics
The NOT operator is used when you want to exclude specific concepts from your search - for example
artificial intelligence NOT computers
To expand upon the NOT operator:
Here they are visually. The first circle is the set of results containing "football". The second circle is the set of results containing "hurling".
The shaded area is the set of results than contain "football" AND "hurling"
The shaded area is the set of results that contain "football" OR "hurling"
The shaded area is the set of results that contain "football" NOT "hurling"
Boolean operators are very powerful, but make sure you use the right ones!
On the search page of a resource you might see something like this:
You enter your search term in the first field. Next to the second and third fields, there are dropdown menus that let you choose a Boolean operator. When running a search, 'and' takes precedence over 'or', so the and operator is run first. The search above is
cats AND dogs AND enemies (results will contain all three terms: cats and dogs and enemies)
But if we changed to cats AND dogs OR enemies then because AND takes precedence then 2 sets of search results are combined here: 1. cats and dogs (AND takes precedence, remember?) and then 2. enemies
So your search is (cats and dogs) or enemies. Your results will contain items that contain either
Changing to cats, AND dogs NOT enemies means the search is (cats AND dogs) NOT enemies, so results will contain both cats and dogs but not enemies
Boolean searching can be complicated and perhaps best avoided if you're not confident using operators. You can often search within your search results, and they might be a better option than using complicated strings of Boolean operators
Here's a bigger picture containing the results of various complicated searches involving three different search terms A B and C
Image: A, B and C Boolean operator combinations from The Grasshopper Primer Copyright © Mode Lab 2015 used under a CC-BY-NC-SA-3.0 licence
