Search engines

Most database users do not know how the data are organized in a database system (DBS) they depend solely on the application programs. This is sufficient for most database searches where users can receive large amounts of results quickly and easily, e.g., on literature or other information. Nevertheless, a basic knowledge on where and how to find deeper or more detailed information is quite useful. Due to their complex nature, comprehensive searches (e.g., for processes or patents) are not recommended for beginners. However, most local (in-house), online, and CD-ROM databases provide extensive tutorials and help functions that are specific to the database, and that give a substantial introduction into database searching. 

The initial step is to identify which database, from a few thousands worldwide (about 10 000 in 2002), provides the requested information. The next step is to determine which subsection of the topic is of interest, and to identify typical search terms or keywords (synonyms, homonyms, different languages, or abbreviations) (Table 5-1). During the search in a database, this strategy is then executed (money is charged for spending time on some chemical databases). The resulting hits may be further refined by combining keywords or database fields, respectively, with Boolean operators (Table 5-2). The final results should be saved in electronic or printed form. 

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You will need to know addresses (http //www.) of the major Internet search engines. But search engines are still not perfected and the results may contain certain amount of noise, i. e, irrelevant information. Some companies use tricky things to get your attention we found many NDT related words like TOFD hidden as meta keywords in every page of some websites. If a search engine leads you to this site you will find no actual information provided, not even a single visible instance of the word TOFD. 

Usually an Internet user learns after a while where to go for specific information The Browser provides a bookmark tlmction where all these addresses can be organized by different subjects Typical bookmark folders are Societies, Companies, Journals, Institutes, Databases, Search engines The NDTnet Journal provides a virtual library that makes it easy for newcomers to find NDT sites. Unfortunately, some sites provide a lot of information but do not offer a search function. 

Some may say "We have invested in our own Internet presence (Home Page), so why we should advertise on the Internet Simply informing your established customers of your new Internet address is not sufficient. We ve already discussed some of the challenges users may face in searching for information. Your potential customer may lack the patience to follow hundreds of links of search engine output. 

The huge number of websites on the Internet (about 2,5 billion web pages December, 2002) containing chemical information is a great challenge when one is attempting to find specific information on a topic. Therefore numerous search engines have been developed and offered that provide fast access to the data. 

Recapitulating, large search engines are useful to obtain a fast ovemew of search terms. To get more detailed information one has to enter qualified, specialised portals or even utilize databases (see above). 

If users are inexperienced in searching for information, they should first consult search engines, meta-databases or portals (Table 5-6). Searchers who are familiar with databases may consult known databases (numeric databases, bibliographic databases, etc.) directly, being aware that they might miss new data sources (see Section 5.18). The reliability and quality of data are only given in peer-reviewed data sources. 

Table 5-6. Free-of-charge search engines, inetadatabases, and (chemical) portals.

All the methods of obtaining information via the Internet presented above carry one risk - dead links. Although a search term may be found by a search engine in its own website-metadata database, the original link to the website could be broken and the information is lost. In this book a conscious effort has been made to limit the URLs and to reduce the web address to the index page of the seiwer, to avoid this sometimes annoying problem. 

Choose large search engines or meta-search engines in the case of few or no results if applicable, try OR. 

Specialty search engines are to be preferred if a database or a detailed menu is available in any other case make use of their directory scan more than one to three result pages. The relevance ranking of a search engine may not correspond to yottr preferences. 

Tn general the more well-known a substance is, the more likely it is that information can be found using specialty search engines. The less well-known a substance is. tbe more likely it is that information can be found using major search engines. 

ChemFinder Search Engine—http //chemfinder.cam-soft.com... 

Material Safety Data Sheets for the chemical s manufacturer These are available on the Internet. Lisu.iHy s uii type http //www.xxx.com, where xxx is the manufacturer s name. If this doesn t work, go lo. i search engine or try http //siri.org/msds/ for a general directory to chemical manufacturers. 

CRS provides information on chemical substances and how they are represented in the Environmental Protection Agency regulations and data systems. A search engine for chemicals by CAS number, name, molecular formula, chemical type, definition, or other data identifiers. 

RAPRA free Internet search engine. The number of plastic-related web sites is increasing exponentially, yet searching for relevant information is often laborious and costly. During 1999 RAPRA Technology Ltd., the UK-based plastics and rubber consultancy, launched what is believed to be the first free Internet search engine focused exclusively in the plastics industry. It is called Polymer Search on the Internet (PSI). It is accessible at www.polymersearch.com. Companies involved in any plastic-related activity are invited to submit their web-site address for free inclusion on PSI. RAPRA Technology s USA office is in Charlotte, NC (tel. 704-571-4005). 

Product Locator A product-specific search engine which provides datasheets/MSDS sheets. 

Besides sensitive methods for the analysis of proteins, bioinformatics is one of the key components of proteome research. This includes software to monitor and quantify the separation of complex samples, e.g., to analyze 2DE images. Web-based database search engines are available to compare experimentally measured peptide masses or sequence ions of protein digests with theoretical values of peptides derived from protein sequences. Websites for database searching with mass spectrometric data may be found at http //www.expasy.ch/tools, http //prospector.ucsf. edu/ and http //www.matrixscience.com. 

Like CA, Beilstein is available online, including the useful search engine CrossFire. 

The Internet has become the best source for thermodynamic data. Run a search on something like chemical thermodynamic data on any serious search engine, and you will hnd multiple sources, most of which allow free downloads. The data in the standard handbooks, e.g. Perry s Handbook (see Suggestions for Further Reading section of Chapter 5), are still correct but rather capricious in scope and likely to be expressed in archaic units like those sprinkled here and there in this book. 

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