Search engines are very different from subject directories. While humans organize subject directories, search engines rely on computer programs called spiders or robots to crawl the Web and look for words on each page.
Subject directories are databases with references to websites. The websites that are included are hand picked by living human beings and classified according to the rules of that particular search service.
Directories are very useful when you have no more than a general notion of what you are looking for.
If you use the search form when exploring a directory, remember that you are not searching the text of the actual webpages of a particular site. Instead you are searching the text contained in the site title and the description of the site. These are composed by the directory editors, and are often based on suggestions from the site owners themselves.
They search several search engines and directories at the same time, trying to extract the most relevant hits from all of them.
You might find it useful to start your searching with one of these, just to get a general feeling for what is out there.
use search engines effectively, it is essential to apply techniques
that narrow results and push the most relevant pages to the top of the
When conducting a search, break down the topic into key concepts.
Connecting search terms with AND tells the search engine to retrieve web pages containing ALL the keywords.
Science AND Fair
The search engine will not return pages with just the word science. Neither will it return pages with the word fair . The search engine will only return pages where the words science and fair appear somewhere on the page. Thus, AND helps to narrow your search results as it limits results to pages where all the keywords appear.
Click to try it! How many matches or hits?
Linking search terms with OR tells the search engine to retrieve web pages containing ANY and ALL keywords.
When OR is used, the search engine returns pages with a single keyword, several keywords, and all keywords. Thus, OR expands your search results. Use OR when you have common synonyms for a keyword. Surround OR statements with parentheses for best results. To narrow results as much as possible, combine OR statements with AND statements.
AND NOT tells the search engine to retrieve web pages containing one keyword but not the other.
Saturn AND NOT car
The above example instructs the search engine to return web pages about the planet Saturn but not web pages about the car. Use AND NOT when you have a keyword that has multiple meanings. The need for AND NOT often becomes apparent after you perform an initial search. If your search results contain irrelevant results (e.g., Saturn the car rather than Saturn the planet), consider using AND NOT to filter out the undesired websites.
PLUS & MINUS
In many search engines, the plus and minus symbols can be used as alternatives . The plus sign (+) is the equivalent of AND, and the minus sign (-)
is the equivalent of AND NOT. There is no space between the plus or minus sign and the keyword.
NOTE: AltaVista's Simple Search requires the use of plus and minus rather than AND, OR, and AND NOT.
Surrounding a group of words with double quotes tells the search engine to only retrieve documents in which those words appear side-by-side. Phrase searching is a powerful search technique for significantly narrowing your search results, and it should be used as often as possible.
For best results, combine phrase searching with (+/-) or use (AND, OR, and AND NOT) logic.
+"science fair" +electricity
The above example tells the search engine to retrieve pages where the words science fair appear side-by-side and the word electricity appears somewhere else on the page.
NOTE ON (+/-)
When a phrase search is combined with additional keywords using implied (+/-), you must put a plus or minus sign before the phrase as well as the other keywords. If the search involves a phrase with no additional keywords (e.g., "science fair"), the plus sign before the quotes is optional.
PLURAL FORMS, CAPITAL LETTERS, AND ALTERNATE SPELLINGS
Most search engines interpret lower case letters as either upper or lower case.
Like capitalization, most search engines interpret singular keywords as singular or plural. If you want plural forms only, make your keywords plural.
A few search engines support truncation
or wildcard features that allow variations in spelling or word forms.
The asterisk (*) symbol tells the search engine to return alternate
spellings for a word at the point that the asterisk appears. For
example, electric* returns web pages with
Field searching is one of the most effective techniques for narrowing results and getting the most relevant websites listed at the top of the results page. A web page is composed of a number of fields, such as title, domain, host, URL, and link. Searching effectiveness increases as you combine field searches with phrase searches and Boolean logic.
The above TITLE SEARCH example instructs the search engine to return web pages where the phrase science fairs appears in the title and the word electricity appears somewhere on the page. Like plus and minus, there is no space between the colon (:) and the keyword.