Search Tips
- Remember the Internet is a self-publishing. Everything you find via Internet Search Engines must be evaluated for its appropriateness for research use. For guidelines on how to do this, please see Evaluate Web Resources.
- Get to know your favorite search engines. Every tool has different rules. How big is its database? How often is it updated? How is the data indexed and searched? What advanced searching techniques are offered? How are results displayed?
- Read a search engine's online help screens. Here you will find the search engine's default settings and special search instructions that will help you retrieve desired results.
- If you are searching for a broad subject area, try subject directories first. Subject directories often offer a collection of links that have been recommended by subject specialists.
- Always try more than one search engine. They are all different and will return different results.
- If your search produces no results: check your spelling, then try synonyms or variations on words. Also try to be less specific or try another search engine.
- If your search produces too many results: Try to be more specific, use the Boolean AND operator to narrow your search. Try to think of words that are unique to what you are looking for. Some words are of little value because they identify lots of documents.
Words to know when using search tools:
- algorithm
- A set of rules for performing a task.
- Boolean logic
- Search technique that uses certain logical operators to combine search terms. The basic Boolean operators are AND, OR and NOT. Variations on these operators, sometimes called proximity operators, may be supported by some search engines. These operators include ADJACENT, NEAR and FOLLOWED BY.
- harvest
- The process by which a robot downloads and indexes Web documents.
- hit
- A result of a search query.
- phrase searching
- Allows you to search for words together in an ordered phrase, i.e. "special education." For most search engines, you can indicate a phrase search by placing your keywords in quotes.
- query
- The request a user types into the search interface and submits to the search engine.
- relevancy ranking
- Almost all search engines display results by relevancy. Results are ranked in the display list according to how often your query terms appeared in the document, the placement of terms within the document, and other criteria.
- results set or list
- The set of documents retrieved by a search tool in response to a search query.
- second generation search services
- Organize search results by peer ranking, concept, site and domain, rather than by relevancy. For example, Direct Hit ranks according to sites other searchers have chosen from their results to similar queries.
- spiders, robots, or crawlers
- Automated programs that continually travel the Web looking for new documents to add to the search engine's database.
- stopwords
- Words that are so common to the language that they are usually ignored by the search tool. For example: and, this, that, who, what, where, when.
- term frequency
- The number of times a user's keywords appear within a document.
- truncation
- Many search engines allow you to truncate words. This is helpful if you are not sure of the word's spelling or ending. (i.e. quilt* retrieves quilt, quilting, quilts, quilted, quilter) Common truncation symbols are the asterick * or the question mark ?.
Web Search Tools
There are three basic types of tools:
- Search Engines & Meta-Search Engines
- Subject Directories
- The so-called "Invisible" or "Deep" Web.
1. Search Engines & Meta-Search Engines
A search engine is a searchable database of Internet Files. These databases are built by automated programs, often called "spiders," "crawlers," or "robots," that constantly visit Web sites in order to create an index of Web pages. Each will have its own search strategies with varying results. It is important to read the online help screens provided by the individual search engines for tips and advice on how to search.
A meta-search engine provides a single search interface for querying multiple search engines simultaneously. They are convenient to use, but offer few searching options. Some of the most popular include: Dogpile, ixquick, MetaCrawler, and Vivisimo. Some meta-search engines collate search results in a single list, while others present separate lists of results for each search engine that was searched.
- 1st Generation Search Engines (i.e. Alta Vista, Lycos, Hotbot) return results by relevancy ranking. Relevancy is based on the number of times your search terms appear in a given page and the placement of your search terms on that page (i.e. if your term appears is the title of the page is consider more "relevant".)
- 2nd Generation Search Engines (i.e. Google, Teoma) do not employ relevancy ranking technology. They organize search results by peer ranking, or cluster results by concept, site or domain. For Example:
Google ranks by the number of links from pages ranked "important" or "high quality" by the service.
Direct Hit ranks according to sites other searchers have chosen from their results to similar queries
Applied Semantics (fomerly Oingo) performs a concept processing of your search and attempts to identify the probable intended meaning.
When to use a search engine:
- When looking for something specific or when you have a narrow topic.
- When you want to search the full-text of millions of web pages.
- When you want to retrieve a lot of results.
- When you are looking for a specific site.
When to use a meta-search engine:
- When you have an obscure topic
- When you want to retrieve a small number of relevant results from a variety of search engines
- When you are having trouble locating information in other search tools
- When your search is not complex
For a listing of Search Engines and Meta-Search Engines and their characteristics, please visit the RWU Library's Web Resources Page.
2. Subject Directories
Unlike search engines, subject directories rely on human input. They offer a collection of links to Internet resources that are organized into subject categories. Most directories are also searchable.
There are basically two types of subject directories:
- Academic and professional directories that have been created by librarians or subject experts. These directories are usually affiliated with an academic institution and are intended to help users find high quality sites in major topic areas. Examples of extensive subject directories created by academics and scholars include: Infomine: Scholarly Internet Resource Collections, BUBL Link, Librarians Index to the Internet, and the World Wide Web Virtual Library.
- Commercial Portals that are intended to serve the general public. They often include broader based topics such as entertainment, sports, news, and travel. Advertisement is the major source of revenue for these portals. When selecting sites for inclusion in their directories, they may not adhere to the same selection criteria that you find in academic or professional directories.
When to use a subject directory:
- When you want to find what is available on a broad topic area. Directories support browsing.
- When you want to explore various aspects of your topic area.
- When you want to find quality sites evaluated by a subject expert or librarian.
- When you want to avoid looking at low-content documents that often turn up in search engine results.
3. "Invisible" or "Deep" Web Search Tools
Deep Web search tools are used to find content that is stored in databases which cannot be indexed by regular search engines. They are also useful for locating non-textual files, such as multimedia files, graphical files, software, and PDF documents. Examples of deep web information include items stored in a database or a directory, such as phone books, patents, laws, dictionary definitions, digital exhibits. Information that is new and dynamically changing in content, such as news, stock prices, job postings are other examples of the deep web.
Deep Web Search Tools often resemble Subject Directories in that they are often arranged by topic area. For example, Complete Planet offers a topic area presentation for its links to 90,000 searchable databases and specialty search engines. You might also note that a good subject directory will also link to database sites on the Web. And to further confuse things, some search engines also feature searchable databases as part of their package of services. For example, you can do separate searches in Alta Vista for news, yellow pages, MP3/Audio Files, etc.
When to use the Deep Web:
- When you want information that is normally stored in a database or directory, such as a phone directory, or a searchable collection of laws.
- When you want dynamically changing content such as the latest news, job listings, stock prices, airline prices, etc.
- When you want a particular file type, such as an image or PDF file.
Sample Deep Web search tools include: Direct Search, Complete Planet, and The Invisible Web.
