Types of search tools

By John P. Healy

 

1)     Subject Directories

a.      Subject directories are specialized Web sites that select other Web sites and organize them under broad subject headings such as Art, Education, Recreation, and science.  

b.     You can either browse under broad topics until you find the specific subject you want or you can conduct a search within the subject directories using one or more keywords.  

c.     Subject Directories are best when looking for

                                                              i.            A popular topic (computer games, history of Baseball)

                                                            ii.            A broad topic (art history as apposed to a picture of Leda and The Swan)

                                                          iii.            A specialized database ( a Web site created by a subject expert or other interested party who collects URL’s and makes them available from one Web page) www.oz.net/~cyndihow/sites.htm

d.     subject directories

                                                              i.            www.yahoo.com

                                                            ii.            www.webcrawler.com

                                                          iii.            www.about.com

                                                         iv.            www.go.com

2)     Search Engines

a.      Search engines, unlike subject directories, are comprehensive indexes of the internet.  While there goal is to have every word of every Web page indexed in there database, this really isn’t possible; even the biggest search engine indexes about 60 to 80 percent of the Web.  The databases are created by computers called robots, spiders, WebCrawler’s, or worms that work constantly to collect and index Web pages.

b.      You query a search engine by typing in keywords.  The search engine then looks for your keywords in its enormous database.  All documents containing your terms are returned in ranked results list, or “hit” list.

c.     Ranking algorithms are formulas used to determine the older in which the results are displayed: the results most relevant to your search term and operators appear at the top of the list, and the least relevant results appear at the bottom of the list.

d.     Search engines

                                                              i.            www.hotbot.com

                                                            ii.            www.lycos.com

                                                          iii.            www.excite.com

                                                         iv.            www.nlsearch.com

3)     Boolean Logic

a.      Language is given meaning through context.  Boolean logic, so named for George Boole, a mathematician in the middle 1800’s, deals with the logic relationships between things.

b.     You apply Boolean logic through the use of Boolean operators. The basic Boolean operators – AND, OR, and NOT – are used to refine your Web searches by allowing you to specify the relationship between your search terms:  which terms must be included in all results pages (AND), which terms must be excluded (NOT), and which alternate terms should be included if found (OR).

Example of Boolean logic:

Cats AND Dogs

                           

 

Cats OR Dogs

                            

 

Cats NOT Dogs

                           

4)     Beyond keywords

a.      The basic techniques for refining your results are to search for unique phrases and to include or exclude terms.  A few tricks common to many of the search engines are worth remembering.

                                                              i.            “ ” Use quotes to surround words to be kept together in their specified order.  This is also known as a phrase search

                                                            ii.            + Use the plus sign in front of a word to insure the word appears in all hits. Do not leave a space between the operator (+) and your search term.  You do need a space between search terms.

                                                          iii.            – Use the minus sign in front of a word to insure it does not appear in hits.  Do not leave a space between the operator (-) and your search term.  You do need a space between search terms.

5)     Basic Search Tips

a.      Broaden your search using Boolean OR.

b.     Narrow your search using Boolean AND or NOT.

c.     Alter your search terms.

d.     Use the plus sign, the minus sign, and quotes to refine your search.

e.      Limit your search to particular field such as title, URL, or Internet domain.

f.       Beware: just because it’s in print and on the Web doesn’t mean it’s true.  You need to evaluate what you find on the Internet just as you would evaluate other information that comes to you from unfamiliar sources.