Both databases and search engines use the 3 Boolean operators and, or, not, but they use them differently. You must learn them.
Here is how you use the 3 operators in Google.
AND (click for example) - All the search terms must appear in the results entries
Google uses the implicit "and" because it is assumes you want all the words in your query.
You do not need to write the operator.
["climate change" canada]
OR (click for example) - Either one of the terms on either side of the operator will be searched
In Google you must capitalize OR. If you don't it will be seen as a dead word.
["global warming" OR "climate change"]
[define:x] will search for online definitions of your term.
E.g., [define:tube] (click).
The result will be shown in a box at the top of your search results.
Add the word [study] or  or (click) to your query to focus your search on primary sources.
Add [table] or [statistics] or [graph] or [spreadsheet] to retrieve statistical information.
"phrase searching" (click for example)
To find phrases put the search terms between double quotation marks. The terms will be searched as is, in the order they appear between the quotation marks. Search engines accept phrase searching.
E.g., "eating disorders", "once upon a time", "american school of paris"
site:x (click for example)
Use [site:x] in Google to restrict your search to specified sites.
Domain extensions: [site:edu], [site:gov], etc.
Country extensions: [site:ca], [site:fr], etc.
Full sites: [site:youtube.com], [site:nytimes.com], etc.
filetype:x (click for example)
Using [filetype:x] will restrict your results to the desired file format.
Flash file: [filetype:swf]
Document type: [filetype:pdf], [filetype:jpg], [filetype:ppt, etc.
Hitwise - stats
How Search Works (video by Google)
Learn How to Search (lessons by Google)
Credibility: Truth & Trust on the Web (2011 slideshow by Google)
A Google A Day challenge (test your skills)
Get more out of Google (infographic)
Is Google making us stupid (from Nicholas Carr)
This aforemention article was first published inThe Atlantic in 2008 was the genesis to his book The Shallows, What the Internet Is Doing to Our Brain (2010).
The Shallows certainly gives a modern twist to McLuhan's the medium is the message!