Basic search commands




Дата канвертавання22.04.2016
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INTERNET SEARCHING

This is a guide to making effective use of the Internet, including help with search strategies and an introduction to the facilities of some leading search engines.



BASIC SEARCH COMMANDS

The more specific you are able to make your search, the greater the chances of finding what you are looking for.


If you want to ensure that a search engine finds the pages that have all the words you enter, add a plus sign in front of each search term - e.g.:
+upper +limb +disorders
If you wish the search engine to locate pages that have one word in them but not another word, you should use the minus symbol - e.g.:
+tumour -benign
A phrase search (enclosing a phrase within quotation marks) is a very useful way of pinpointing exactly what you are looking for. The search engine will look for pages where the terms appear in exactly the order specified. For example +upper +limb +disorder may retrieve a number of irrelevant references ('false drops'). Upper may appear in one paragraph, limb in a second and disorders in a third relating to another subject (e.g. 'mental disorders'). A phrase search should overcome this problem:
"upper limb disorders"
To improve your searching, you may wish to use a combination of symbols (+, -, " "):
"chemical sensitivity" - toluene -benzene
Nearly all the major search engines allow you to search in this way*
(* Alta Vista and Google operate automatic phrase detection (which means you do not need to use quotation marks), and LookSmart does not use the + and - symbols)
You may wish to locate pages that contain any of the search terms (the equivalent of a Boolean or search on the Library CD-ROMs). AltaVista, Excite, Go To, LookSmart, Netscape, Snap, WebCrawler and Yahoo will automatically search this way when you enter a series of terms. Most search engines will first list pages that contain all of the terms, then list those that contain some/any of the terms.
Many of the major search engines (AltaVista, GoTo, HotBot, MSN, Search, Northern Light, Snap) allow you to do title searching entering title: e.g.:
title: chemical classification (t: chemical classification in Yahoo)
'Wildcard searching' (*) enables you to search for plurals or variations of a word:
Chemical* will find 'chemical' and 'chemicals'
A couple of search engines (Lycos and Northern Light) do not require the use of a wildcard symbol. You can just enter the stem of a word and they will search for variations of that word.
BOOLEAN SEARCHING
If you search CD-ROM databases, you will probably be more familiar with Boolean commands (AND/OR/NOT) than with +,-,"", which you can use as alternative commands when searching the Internet.
OR

This is the equivalent of free entering of terms (see above). All the major search engines apart from Google, Yahoo and LookSmart use the OR command, though Yahoo and Looksmart perform an OR search by default.


AND
This type of search involves searching for at least two keywords, both of which must appear in the results. It is the equivalent of the + command (see above). All the major search engines apart from Google, Yahoo and Looksmart use AND searching.

AND NOT
This is the equivalent of the - command (see above). Altavista, MSN Search, Netscape and Snap use this command. Be careful when using this command as you may inadvertently exclude material that would be useful to you, as it eliminates records containing both terms.
NEAR
This is 'proximity search' is similar to, but not always as precise as the " " command (see above). Different search engines define 'near' in different ways. In AltaVista it means that terms must appear within ten words of each other, whereas in Lycos, it means within twenty-five words, but that can be changed by adding a / symbol and any number e.g.
Ergonomic NEAR/1 design


LEADING SEARCH ENGINES
The 'Big Six' search engines are:
AltaVista

Excite


HotBot

Infoseek


Lycos

Yahoo
The following is a description of two of them ('Altavista', and 'Yahoo' )


AltaVista (www.altavista.com)

This is one of the most powerful and largest of search engines with around 550 million indexed pages (only FAST and Google index more pages). It is very popular with researchers because of its wide range of power searching commands.




BASIC SEARCH (using Basic Search Box)


TYPE OF SEARCH

ACTION REQUIRED

EXAMPLE

Plain English Question

Phrase


AND search

OR search

NOT search

Wildcard


Proximity Search
Nested Search
Case-sensitive search

Date search


Field search

(e.g. text:

title:

Weighted keyword search



Type question in search form text box
Type phrase enclosed by double inverted commas
Place a + sign in front of each word or phrase that should appear in the results
Type words or phrases separated by spaces
Place a - sign in front of a word or phrase that should be excluded from the results
Place an asterisk at the end of or within a word with at least three letters of the search term
See 'Advanced Search'
See 'Advanced Search'
Use lowercase letters to find any combination of upper and lower case letters. Use capital letters to find an exact match of your search term

See 'Advanced Search'
Type field-search keyword in lowercase, followed by a colon and your search word or phrase


See 'Advanced Search'

What is chemical sensitivity?

"occupational hygiene"

+dioxins +toxicity

classification index

+cancer -smoking

asthma* or fib*s

Directory

(this would find Directory)


directory

(this would find Directory and directory)

text: "occupational exposure"

title: "Exposure Limits"


You will often find the need to refine your searches, because the initial search retrieved too many results. This can be done in several ways:




  1. by adding new terms to the original query in the Basic Search Box, preceded by + and - signs as appropriate;

  2. by using the 'Field search' facility described above;

  3. by clicking on the ‘Refine’ button on the Basic Search Form. This sorts the search results in to topics, presented in order of likely relevance to the search. Using this thesaurus facility helps with selecting additional terms for the search, eliminating superfluous words or phrases, and with exploring topics related to the search request.


ADVANCED SEARCH (using Advanced Search Form)
This uses the same rules as Basic Search for several search-related activities: defining words and phrases, capitalisation, field searching and using wildcards, but has important additional functionality. Instead of using + and - signs, the Boolean operators AND, OR and AND NOT are employed in the Advanced Box. The following additional features are available:


  1. Proximity Search

NEAR can be used to find terms that appear within ten words of each other.




  1. Nested Search

Search words and phrases can be grouped in parenthesis to form more complex search statements.




  1. Date Search

A search can be limited to cover a specific time period by specifying a date or range of dates.




  1. Keyword Weighting

Particular keywords can be identified as more significant than other keywords, so that documents containing those words will be listed first in the search results.




  1. Expanded Results List

Unlike Basic Search, hits are not limited to a maximum of 200.




TYPE OF SEARCH

ACTION REQUIRED

EXAMPLE

Plain English Question

Phrase


AND search

OR search


NOT search


Wildcard


Proximity search

Nested Search


Case-sensitive search


Date Search

Field Search

Keyword Weighting


Type question in smaller search box on form
Type phrase enclosed by double inverted commas
Use AND between letters or phrases to indicate that both/all should appear in the results
Use OR between words or phrases to indicate that either should appear in the results
Use AND NOT in front of the word that should be excluded from the query
Use an asterisk at the end of or within a word with a minimum of three letters of the search term
Use NEAR to find words or phrases that appear within ten words of each other
Use parenthesis to group search expressions into more complex forms
Use lowercase to find any combination of upper- and lowercase. Use capital letters to find an exact match of search terms (see example)
Type the date or range of dates in the From and To boxes (DD/MMM/YY)
Type field-search in lowercase, immediately followed by a colon and the search word/phrase
In the ‘Sort by’ box in Advanced Search form, type the word/phrase that should be given the greatest weight. Web pages meeting this criteria will appear first in the list

What are the health effects of air pollution?

"human sciences"

chemicals AND carcinogenic AND risk

health or wellbeing


pollution AND NOT air


disab*


levels NEAR exposure

noise (control OR sources)


“Scanning Mobility Particle Sizer”

15/May/01

title: Case Reports





Yahoo (www.yahoo.com)
This is a searchable directory of Web pages. Because of its hierarchical structure, it is a useful when you are trying to identify good relevant sites on a chosen subject. A topic can be searched by ‘Category’, by ‘Web Sites’ or by ‘Web Pages’. It remains the most popular search service on the Web. If a search fails to locate a match, then matches from ‘Google’ are displayed. The 'Google' search engine has over 1.3 billion pages indexed.
Quick Reference

TYPE OF SEARCH

ACTION REQUIRED

EXAMPLE


Plain English Question

Phrase Search

AND search

OR search

NOT search

Wildcard search


Date search
Field Search

Avoid. Use phrase or AND search
Type the phrase enclosed by double inverted commas
Place a + sign in front of each word or phrase that should appear in the results
Type words or phrases separated by a space
Place a – sign in front of a word or phrase that should be excluded from the results
Place an asterisk at the end of or within a word with at least the first three letters of the search term

This search needs to be done through the Search Options Page (click on ‘Advanced Search’), where a time period can be selected.


To search titles of web page documents, use t: in front of word/phrase

“ergonomic design”

+occupational +stress

hazards risks

cancer – malignant

occupation*


t: "nuclear energy"


The Search Options Page that gives enhanced control of the search. The search can be refined in different ways:




  1. it can be limited to Yahoo categories or web sites by selecting the appropriate button under 'Select a search area';

  2. by selecting a search method: ‘Exact Phrase Match’; Matches on All Words (AND); Matches on Any Words (OR)



Yahoo's Web Directory
This directory is a very detailed outline of what is available on the web. Because this outline is searchable, it assists the searcher in focusing in on the particular information required. First a topic is chosen, then the searcher can 'drill down' through the resulting pages which include subtopics that become more and more specific. The stages are as follows:


  1. click on topic category on home page to display its subtopics

  2. search form gives 2 options: a) choose all of yahoo (from drop-down menu)

b) limit search just this category

  1. the lower part of the topic page provides the next level of subtopics plus descriptions of them. The numbers in brackets give information about how many entries are listed under the subtopic.

  2. You will reach a page that includes a set of links for specific web sites plus brief site descriptions



Further Surfing
Best Search Sites on the Web
http://www.zdnet.com/anchordesk/story/story_3871.html
Offers a detailed review of 15 search services


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