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This guide introduces different search tools with selected examples.
Common search techniques among internet search engines are also highlighted.
Human powered databases with multi-disciplinary subjects.
Web sites are usually annotated and suggested by authors.
Sites are selected and indexed into the databases by specialists.
Browsable by hierarchical structures; usually come with a searching feature.
Links are not updated regularly.
Good for overview of broad and popular topics.
Examples:
| Google Directory | http://directory.google.com/ |
| Yahoo! Directory | http://dir.yahoo.com/ |
| BUBL Link | http://bubl.ac.uk/link/ |
| CompletePlanet | http://aip.completeplanet.com/ |
| DMOZ Open Directory Project | http://dmoz.org/ |
| INFOMINE | http://infomine.ucr.edu/ |
| Intute | http://www.intute.ac.uk/ |
| The Librarians’ Index to the Internet | http://lii.org/ |
| The Resource Discovery Network | http://www.rdn.ac.uk/ |
| The WWW Virtual Library | http://www.vlib.org.uk/ |
Created by subject experts with quality criteria for selection and evaluation.
Searchable and browsable.
Links are not updated regularly.
Good for finding information in specific subject areas.
Examples:
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Intute: Arts and Humanities |
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Intute: Social Sciences |
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Intute: Science, Engineering & Technology |
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Intute: Health & Life Sciences |
Crawler-based; sites are automatically collected by computer programs.
Sites are revisited and updated regularly by robots or spiders.
Extensive coverage, in terms of billions of records.
Search hits are ranked by relevancy instead of by quality.
Evaluation of the quality of web sites is a 'must'.
Good for finding comprehensive and specific information.
Examples:
| http://www.google.com/ | |
| Google Scholar (Beta) | http://scholar.google.com/ |
| Yahoo! Search | http://search.yahoo.com/ |
| AlltheWeb | http://www.alltheweb.com/ |
| AltaVista | http://www.altavista.com/ |
| Ask.com | http://search.ask.com/ |
Also called 'meta-crawlers' and 'multi-search engines'.
Provide a one-stop search on multiple search engines and subject directories.
Results may be listed by search engines or de-duplicated in a single list.
Time saving and good for getting comprehensive information.
Examples:
| Dogpile | http://dogpile.com/ |
| MetaCrawler | http://www.metacrawler.com/ |
| WebCrawler | http://www.webcrawler.com/ |
| Vivisimo | http://vivisimo.com/ |
Analyse your topic, define search terms, synonyms and related words.
Build a searachable question with your vocabularies.
Combine search terms with Boolean operators.
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OR |
Broadening a search with synonyms and other
related words. |
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| AND |
Narrow a search by different concepts. |
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| NOT (AND NOT) |
Eliminate a concept from a search. |
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| Nesting |
Order of precedence can be changed by using
brackets. |
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Menu Based and Free Forms queries may be used for tuning searches to get accurate results.
Menu Based Query Builder - Available in the Advanced Search with filters limited by languages, file formats, dates, domains and so on.
| with all of the words | words are combined by 'AND' |
| with the exact phrase | search with words in a specified order |
| with at least one of the words | words are combined by 'OR' |
| without the words | eliminate word(s) in a search by 'NOT' |
