Computers cannot understand language so it's important to give them simple and logical instructions. There are four basic techniques you can use to improve your search skills: keyword searching, Boolean expressions, phrase searching, and truncation. All of these techniques can be combined together to create precise or broad searches.
Google's Inside Search Tips & Tricks is very useful resource for learning the basics of searching.
Make sure to use more than Google and Google Scholar - there's so much more out there!
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Most of us are familiar with keyword searches: you enter in words and you get back results which contain those words. It's important to choose your keywords carefully otherwise you will get no results or the wrong results. Use these basic tips to improve your keywords:
When you combine keywords with AND you will only get results which contain all of the keywords joined by AND.
Use AND when you need to narrow a search to contain ALL keywords.
When you combine terms with OR you will get results which contain any of the terms joined by OR.
Use when you want to broaden a search to search for related terms or variant spellings (example: "climate OR climatic OR climates")
NOT is used to specify keywords to ignore. Some search engines and databases don't support NOT (Google uses "-" instead for example). NOT can be useful when you are searching for a word with multiple meanings or need to exclude certain topics from a search.
Truncation is a way to place "wildcard" characters in your searches. This is useful when trying to include word variations in your searches.You need to be careful where you truncate a word - if you truncate too early you may end up with unexpected results that contain unrelated words with the same spellings. The asterisk(*) is the symbol most indexes use for truncation.
You can use parentheses to group different sets of instructions into one, precise search command. Just like in mathematics, the computer processes the statements in parentheses first, and then applies the commands outside of the parentheses to the results.
This search will retrieve results that contain the phrases "house training" or "house train" and EITHER cat or cats. If you truncate cat* you would get way too many irrelevant results including catatonic, catalyst, etc. so only train is truncated in this example.