A web search engine is a software system that is designed to search for information on the World Wide Web. The search results are generally presented in a line of results often referred to as search engine results pages (SERPs). The information may be a mix of web pages, images, and other types of files. Search engines also maintain real-time information by running an algorithm on a web crawler. Internet content that is not capable of being searched by a web search engine is generally described as the deep web.
Besides Google and Bing, that are the most know search engines, there are other search engines such as: Yahoo, Ask.com, AOL.com, Baidu (most popular search engine in China), Wolframalpha, DuckDuckGo.
Searching on Google is easy, at least in principle. You just have to open www.google.com and look for any word you want. Let’s try, for example, the word "course". It gives us 1,790,000,000 results in 0.57 seconds (when this unit was written). This makes us wonder whether so many results are necessary especially if we do not have several millennia to check them all, and why this strange measurement of 0.57 seconds.
If we press F5 to repeat the search, different quantities may appear, both for the number of results and for the time used to display them.
In the first results we see definitions, for example from Wikipedia, and some elearning platform, among others. But what if this is not what we were looking for? What if these results do not help us or we think they are not well oriented? What if I do not want definitions of "course" in our searches, but we are for a specific course in a specific place?
To solve this issue and limit our searches we can use different searching strategies such as:
Meaningful searches
Use unique, specific terms – When you search for specific information you should use relevant words otherwise you will come across a lot of unnecessary data.
Don't use common words and punctuation - Terms like ”a” and ”the” are called ”stop words” and are often overlooked as well as the punctuation. There are exceptions of course. Common words and punctuation should be used when searching for a specific expression inside quotes.
Capitalization – Most of the search engines do not discern between uppercase and lowercase, even within quotation marks.
Excluding searches
•Search for any word and then include with a minus sign (-) before those words that you wish to exclude. For example, let's imagine that in my search for "course" we do not look for definitions. We could try it now with «course -definition -definitions» in Google. This means that all results with the words "definition" and "definitions" will be omitted. Once this is done, the results returned by the search are slightly different from the previous ones, and probably will suit better to what we want to find.
•Now, what happens if we search for a word and, in turn, exclude it from the search? Try searching for a word, such as "course" in Google, and then try searching for "course -course". That is, you search and exclude the same term from the search. What do you think the search engine will return? An empty set? Nothing, maybe? Try it.
Exact searches
•Search for any string of words and then do the same search by putting double quotes at the beginning and at the end “XXX XXX”. You will see that two completely different listings appear. Which one fits more to what we are looking for? In normal conditions it will be the second option, simply because when adding the double quotes we are indicating to the search engine to show only webs where our chain appears exactly as we have written it.
The first search will give us a list of pages where at least one of the words of our search string appears, they do not have to be all, or they do not have to be in the same order as we have indicated. With the second option we make sure we consider each and every one of the words that we have indicated and also in the same order.
Search within a web
The site command is site:www.url.com xxx. If we put "site" without the 3w's in Google, the search engine will offer you all the results that there are in a web including its subdomains. If we put the same search but with the 3w's, then the search engine will exclude the subdomains.
Definition searches
When we want Google to define a term for us, we use define: xxx. We can put for example define: course.
Search by file type
You can use filetype: .XXX, for example filetype: pdf. It can be combined with other commands, such as site, if we want to search for a file type in a certain web.
Operator +
By adding a plus (+) just before a search you are telling Google to show you exactly that term excluding synonyms, acronyms and so on.
Operator -
We have already seen it, it is very useful to filter search results excluding certain terms.
Operator |
This horizontal bar means this "or" the other.
Operator *
The asterisk works like a wildcard. When you put it in front of a word and within a sentence you are telling Google to look for the exact phrase that you are asking but that you can exchange the word of the asterisk for another.
Related search
Related: www.url.com. The related attribute is used to obtain results from web pages similar to the one we include.
Searching the cache
cache: www.url.com. The cache search is the backup that Google bots keep of all web pages that have been indexed at some time by search bots.
Search Info
info: www.url.com. The info attribute is useful to get much more information at a glance.
Search for links
link: www.url.com With this command we can discover which are the links pointing to a website and giving it more authority.
Search inurl
This type of search helps us to search for words or expressions in the URLs of web pages. For example we can do a search inurl: www to know how many websites on the network have www.
Search allintitle
It works just like the Inurl search but in this case the search only shows those websites that have that keywords in the title of any of its pages. For example allintitle: "online shop"
Search allintext
This time the search only shows us those websites that have those keywords in the text body of any of its pages. Allintext: training courses
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