Millions of pages of
information are sprouting up on the World Wide Web. It is estimated that there may be
anywhere between 70 million to 100 million pages available as of now.
They contain information, which some one has found it useful and taken
trouble to collate. They may be useful to someone some time the other.
For people using Internet it has become a matter of learning as to how
to search and access the information that is available. With a bit of effort one can
become reasonably apt in homing in on the desired information.
In this short exposition for searching information, I deal with how one
can use search engines effectively. Here I deal with basically two common ways to
search the information:
- Boolean Search
- Phrase Search
In my experience I have found that this leads to the information about
80-90% of the instances. This is, however not an exhaustive way to search all the
different sources of information.
What this exposition attempts to do is to give you is collection of
different search engines and the strategies that to follow. Towards the end there are two
examples which when you try them, they will give you some direct experience of what is
Search engines are tools that use computer programs called spiders
and robots to gather information automatically on the Internet. With this information,
they create a database. Each of the major search engines attempts to do the same
thingnamely, index the entire Webso they handle a huge amount of data.
There are advantages to computer-generated databases. They are
frequently updated, give access to very large collections, and provide the most
comprehensive search results. If you are looking for a specific concept or phrase, a
search engine is the best place to start. And you would be smart to look in more than one,
because each engine gives different results.
Some of the most popular search engines are as follows:
Search Engine Similarities
All of the major search engines are similar in that you enter keywords,
phrases, or proper names in a search form. After you click on search, submit, seek, or
some other command button, the database returns a collection of hyperlinks to your screen.
The database usually lists them according to their relevance to the
keyword(s) you typed in, from most to least relevant. Search engines determine relevance
in different ways.
All search engines have online help to acquaint you with their search
options. Two common search options that most search engines support are
Boolean and phrase searching
. We will briefly discuss these two options below.
The Boolean operators are AND, OR, and NOT.
- The use of AND placed between keywords in your search expression will
narrow the search results.
For example, hiking AND camping would narrow your search so that
you would receive only those sites that have both the words hiking and camping
- Placing an OR between keywords broadens your search results. For example, hiking OR
camping would retrieve those sites that have either the word hiking or the word
camping in them.
- The NOT operator will also narrow the search.
- For example, hiking NOT camping would narrow your search so you would get all
hiking, but not camping.
- In some search engines, if nothing is typed between two words, you can assume an OR is
between them. This is what wed refer to as default setting.
In order to override this setting, youd either have to type AND
between the words or put a + before both words.
Here are a couple of links to other Web pages dealing with Boolean
- Searching by phrase guarantees that the words you type in will appear adjacent to each
other, in the order you typed them.
- Lets say you are searching for information on global warming. If you typed in the
two words global warming separated by a space, the system youre using may
assume that you are in effect saying global AND warming, or in some cases
(depending on the search engine), global OR warming. Your search results would not
be very precise, because the words global and warming could appear
separately from each other throughout the document.
- Most search engines support phrase searching, requiring the use of double quotation
marks around the phrase. We would type "global warming" in our example.
Search Engine Differences
The major search engines differ in the following ways:
- Size of the index.
- Search options (many search engines support the same options but require you to use
different syntax in order to initiate them).
- Update frequency.
- Relevance of the search results.
- Overall ease of use.
It is important to know these differences, because in order to do an
exhaustive search of the World Wide Web, you must be familiar with the different search
tools. You cannot rely on a single search engine to satisfy every query.
Exercise Using Boolean Search
Lets try to find Web pages on recycling plastic products. We
found some general information on recycling in a previous activity by searching the
hierarchical directory of Excite Channels "Web Sites." This time well use
a search engine to find more specific information, specifically about the recycling of
Well use the search engine WebCrawler which was one of the firsts to appear
on the Web. To start, we will type in the keywords we want the Web pages to include.
Well examine the results and then check the help screen to find out how WebCrawler
handles advanced search options. Then well do the search again using Boolean
operators. Well note how our search results were narrowed in size and how the
contents of the pages were more relevant.
Well follow these steps:
- Go to the home page for WebCrawler.
- Type in keywords and start the search.
- Examine the search results.
- Consult search help.
- Modify the search by typing in a new search expression.
- Examine the results.
- End the session.
Let us start the search Engine:
1. Go to the home page for WebCrawler. (Were assuming
your Web browser is already started.)
- Use the mouse to point to the location field and click the (left) mouse button.
The URL of the current Web page will change color. Now you can type in
the URL for WebCrawler.
2 Type in keywords and start the search.
- Type the keywords recycling aluminum containers in the search form next to Search.
- Now click on the Search button.
3 examine the search results.
Notice the large number of hyperlinks retrieved by WebCrawler. They are listed
according to their relevance to the search query, from most relevant to least relevant.
After scrolling down and checking out some of the Web pages retrieved by this search, we
start to think of other possibilities. What if there are some perfect hyperlinks out there
that use the word plastics instead of plastic? How would we construct a
search so we would get Web pages that included the words recycling and products
and plastics or plastic? Were identifying the need to use Boolean
operators, and we need to know whether WebCrawler supports Boolean searching. We hope that
by using Boolean operators, well retrieve not only more relevant results but also
fewer results. We could most easily find out whether WebCrawler supports Boolean searching
by accessing its online help.
4 Consult search help.
- Click on the help
button on the left side of the screen.
A partial list of the search help topics appears.
We discover that WebCrawler does support Boolean searching. We
can use AND, OR, and NOT. Farther down on the "Advanced Searching" page, we also
learn that if there are ANDs and ORs in one search statement, then parentheses must be
used to guarantee good search results.
- Click on the WebCrawler icon at the top
left of the screen.
You should now be back on the WebCrawler home page.
5 modify the search by typing in a new search expression.
- Type recycling and aluminum and containers
This search expression will retrieve hyperlinks to those sites that
have the words recycling AND containers (must have both words) AND aluminum
(must have either one).
6 examine the results.
Take a few minutes and explore the first Web pages retrieved. Notice
that we received significantly fewer results by using the Boolean search operators.
- To read the summaries or annotations of the Web pages, click on summaries.
Note that you can also click on Similar Pages at the end of each
annotation. This will lead you to other pages that are related to this particular page.
7. End the session.
Wasnt that easy? Lets end this session and do another
activity. You can stay online and continue to the next activity or end this session now.
- To disconnect, click on File in the menu bar and select Exit from the
Exercise for Boolean Search finished
Exercise Using Phrase
Searching to Find Information
In this activity, we will open Infoseek and look at the online help
before we begin searching. We will type in the phrase currency exchange rates using
the syntax that is particular to Infoseek, and we will examine the results. Well
have you bookmark the best site we find so that you can start building your own reference
library. Well follow these steps:
- Go to the home page for Infoseek.
- Read the help screens in Infoseek.
- Use the search form provided and type in a search expression.
- Examine the results and click on a hyperlink that appears to have the information
- Find the currency exchange rate for Indian Rupee.
- Bookmark it!
- End the session.
Once you see how easy it is to find an answer to a reference question
on the World Wide Web, you may never want to comb through newspapers or journals again.
And after you make a bookmark to the site that provides the answer, youll be able to
flip to the information whenever you need it in a few seconds. Lets go find it!
1 Go to the home page for Infoseek.
Use the mouse to point to the location field and click the (left) mouse
The URL of the current Web page will change color. Now you can type in the URL for
2 Read the help screens in Infoseek.
Notice that in Infoseek, you must place quotation marks before the
first word and after the last word in the phrase you are searching for. This will ensure
that the words in the phrase appear together.
3 Use the search form provided and type in a search expression.
- Scroll up to the top of the page and click on Infoseek.
- Type the phrase "currency exchange rates" in the search form provided
and click on seek.
4 Examine the results and click on a hyperlink that appears to have
the information you need.
The first page or two of results should contain the most relevant
resources. Find a resource in your hit list that most likely would have the information
you are seeking. In this activity, well click on a Web page entitled "Currency
Exchange Rates...Sonnet Financials Daily Currency Rates as provided by
Reuters." If you find it, click on it. If not, click on another Web page title that
you think will help you find the information.
- Click on Reseller Currency Exchange RatesInterlink Communications System. Find
the currency exchange rate for the Indian Rupee.
- Click on the hyperlink or a similar resource and explore it.
5. Find the currency exchange rate for the Indian Rupee.
6 Bookmark it!
After finding this informative Web page, you may want to locate it
again quickly, so lets put it in your bookmark list.
- Point your mouse to Bookmarks in the location toolbar and click.
- Point your mouse to Add Bookmark and click.
The URLs title is automatically added to your bookmark list. You
can check the list to see that this happened.
- Click on Bookmark again and see that the title of the location is there.
You can access this page later simply by clicking on it.
7 End the session.
- Click on File in the menu bar and select Exit from the menu.
If youre not using your own computer, you may want to delete your
bookmarks at this time.
End of Exercise on Phrase searching
© 1996, 1997, 1998 Dr. Raj Mehta. All rights reserved.