The information provided on the Internet is overwhelming. One of the instruments to find relevant information is search engines. Search engines usually cover part of the web. They differ in many respects:
- coverage of the index (keywords, URLs, titles of web pages; some search engines allow you to search in several indices simultaneously)
- frequency of the indexing (some search engines are not up-to-date)
- how user-friendly is a search engine
- response speed
- presentation of results
- relevance of the results
Please note that some publishers prohibit search engines to index the content of their databases. In order to find articles which are present in the databases of these publishers to ensure optimal results, you will have to use the bibliographical databases.
Always use more than one search engine for the same request in order to obtain optimal results. There are several kinds of search engines:
- General search engines.
These engines differ in volume, search functions, the way of presentation and their relevance with regard to subject fields. Some search engines are: - Meta search engines.
Search engines which automatically employ several others simultaneously. Often results are automatically deduplicated and sorted in several sections. Examples are: - Specialized search engines.
They target addresses, ftp-sites, newsgroups, news, catalogues, bibliographical databases, full text journals, software, shareware, multimedia etc. on one or more subject fields. Examples:
Access to the full text files depends on the licences held by the library. Nearly all search engines are extending their sites to become web portals where services are also offered, e.g. e-mail services, personalized information, subject guides, news etc.
