Boolean: Boolean searching refers to the capability to perform operations on multiple word searches so that all words will be in resulting record (AND), any one word will be in resulting records (OR), or a specified term will not be in resulting records (NOT or AND NOT). In Full Boolean searching, parentheses can also be used nest Boolean operators. The + - system is a variation on traditional Boolean searching.
+ - System: Rather than using the more traditional Boolean operators, this system assumes an OR operation unless a + sign is put directly in front of the word to designate that that term is required (an AND operation) or a - sign is put directly in front of the word to designate that that term should not appear (a NOT operation). In this system, the + or - must appear directly in front of the search term with no intervening spaces.
Categories: All the subject directories arrange sites by subject categories. Two numbers may be given under categories. The first represent the number of main subject categories listed on the main page. The second number represents the total number of categories and subcategories accessible from the top page.
Directories: I define Internet finding aids that are arranged by subject and include only selected sites as directories. While they often do have keyword searching, all entries are listed under one or more subject headings.
Fields: Fields searching allows the searcher to designate where a specific search term will appear. For example, words could just be searched in the title, the url, or the first header. To my mind, this is one of the most important capabilities of search engines.
Limits: The ability to limit search results by a specific criteria can be done in a number of ways. Few search engines have the option. The most commonly available limit is the date limit, which limits the results to those Web pages last updated within the specified date span.
Proximity: Proximity searching refers to the ability to specify how close within a record multiple terms should be. The most commonly used proximity search option in Internet finding aids is a phrase search that requires terms to be in the exact order specified within the markings (usually " ").
Ratings: Some of the subject directories include ratings. If used, the kind of rating scale is mentioned here. None of the scales rates the sites solely on information content, so ratings are rarely much of a measurement of the quality of information content for specific sites.
Search Engines: The term more properly refers to any software used to search any database. On the Internet the phrase usually refers to the large databases of Web sites that are automatically generated. These Internet search engines use a software robot (or spider) that seeks out and indexes Web sites. Some search engines include other Internet resources in addition to Web sites.
Size: For the Internet subject directories, size refers to the number of unique entries in the database, according either to online documentation or correspondence with the company. In a subject directory, size is not necessarily a measure of quality. One method of comparing the sizes of the Internet search engines is to compare the number of results from specific searches. See the statistics page for search engine rankings using this method.
Sorting: One option lacking from almost all Internet search tools is the ability to sort the results of a search. Typically, search engines will try to sort the results by "relevance." Rarely can the search request an alphabetical, chronological, or location sort.
Style: In the subject directories, the style in which the descriptions/reviews are written can make a difference in how valuable the they are. Those written in a popular style may have more words but less information than those written in a descriptive style.
Truncation: Also known as stemming, this search technique concerns the ability to search on a word root that can have multiple endings. If a symbol is used, it is most often an asterisk. Thus colleg* will return hits on college, colleges, collegium, collegial, etc.
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