Advanced search facilities in search engines allow you to submit more complex searches, making your search more precise.
Boolean Operators
Boolean operators are used to combine the words or phrases that you choose to search by. If you would like to understand how Boolean operators work in more detail, the Boolean Machine may be useful.
The Google advanced search uses Boolean concepts and makes the search easier by the use of boxes explaining the type of search that you can carry out. For example, you can search for web pages that have:
All these words (This is like the “AND” Boolean Operator)
This exact wording or phrase (this can be done in the simple search box by using quotation marks)
One or more of these words (this is like the “OR” Boolean Operator)
And you can ask for pages to be excluded by selecting ‘any of these unwanted words’ (this is like the “NOT” Boolean Operator.)
Limiting Your Search
In addition to the use of Boolean operators you can also use Google's advanced search features to limit your search by:
Language
You can use the language drop down box.
File Format
This is a specific feature of Google which allows you to search for specific type of files - e.g. Portable Document File (.pdf), Word (.doc) or Excel (.xls) - on the Internet. This can be particularly useful as some reports and guides are only available in PDF format and not in plain HTML.
Domain
This limits the search by the information that is found in the URL (Uniform Resource Locator) or Internet address. For example, if you wanted to limit a search to only academic institutions in the UK you could put .ac.uk in Google's domain box. Other organisational domains include .edu for US educational organisations, .nhs.uk for the UK National Health Service, .gov.uk for UK Government, .gov for US Government. This can also help you limit to a specific country, by adding the country code into Google's domain box (e.g. .uk for uk; .hk for Hong Kong, .no for Norway). Many of these country domains are easy to guess, although a list of all the country codes is available.
Date
You can limit by when the page was last updated. This can help you reduce the number of results that you get as you can limit your search to the most recent pages or a certain period of interest.
Google's help pages contain further guidance on refining searches.
If you like using Google, you’ll love Summon the Online Library Power Search.