The Chemistry Department uses the program STN Express to perform online searches of the scientific literature. STN Express was developed by the STN (Scientific & Technologies Information Network) International which is run by Chemical Abstracts Service which, in turn, is run by the American Chemical Society. STN can give you access to the major databases in all of the sciences, not just chemistry. We, however, only receive a substantial price reduction for searches performed in certain of the STN databases. Therefore, you should try to restrict your searches to file CA and CAOld. Searches in BIOSIS, for example, are very expensive.
Even in the STN database, searching can get expensive. Therefore, before you perform searches in any full database, you MUST learn how to do a search in the learning file (LCA ), where searching is FREE! Learn how to use the various commands there so you minimize being charged for your mistakes. There is also a FREE learning file (lreg) for the chemical dictionary, the Registry File (reg). The Registry File is VERY expensive and we receive NO DISCOUNTS. So it is imperative that you use the lreg file to master navigation in the Registry File.
The most often used source of information is the file ca. Chemical Abstracts (the company) covers in file ca articles from a wide variety of fields. The only criterion for inclusion is that there is some relation to the broad field of chemistry. So, for example, you will find a relatively complete coverage of biochemical and medical subjects there. The CA file (ca) contains complete bibliographic information from well over 30,000 publications from 1967 to the present.
For articles earlier than 1967, use the CAOld file (caold). CAold covers from 1907 to 1966 (inclusive), but the search capabilities are a more restricted than in the CA file.
In paper form, CA can be searched from its inception in 1907 to the present. Searching the paper edition of CA, even through the use of the Collective Indices, can be very laborious. It is, however, the only way to completely search the pre-1967 chemical literature. As noted above, file caold is limited in its search capabilities. If you need to know about earlier findings (yes, there really was chemistry before 1967!), there is no alternative. Few people, however, search the paper copy for more recent information. If you have access to the Collective Indices, you may find them useful for at least a cursory search of a subject. While the computer is more thorough, the organization of the paper form of the indices often aids one in learning more about relevant topics and sub-topics to be included in a computer-based subject search.
Before we begin, it might be useful for you to simply look at one full bibliographic record just to get a general feel for the information available on an article that appeared in the literature. Some of the information is duplicated (you'll learn later that is due to the format of the output). That aside, you can see that all of the bibliographic information necessary for retrieving the original article is present. There is also an abstract that summarizes the content of the article. At the end of the record there is an extensive list of terms that relate to the content of the article. These are useful in that they suggest words that you could use in constructing a search that would retrieve related articles.
This document walks you through online searching of the STN databases CA, CAOld, and REG, using STN Express as the accessing application/program. It presumes that your computer has direct access to the Internet and contains STN Express. Most of the non-STN Express information is applicable to searching the STN databases, assuming you can gain access via other means.
The document takes you logically through the various features of STN searching for subjects, authors, and compounds, in that order. It introduces various commands on a "need to know" basis, presuming that you are working through the document from top to bottom. If you simply need information on a particular topic, use the CONTENTS listing. The Contents listing is simply a "hot button" outline of the entire document. Click on the topic and you will be taken to that portion of the document. Use the "Back" button on your web application (e.g. Netscape) to return to to the Contents.
Throughout the document you will find explanatory text interspersed with the results obtained from typing a particular command in STN. This may be a little confusing at first, but you will find that lines of text are single spaced (like within this paragraph) and each line of STN results is separated by a double space (as between this and the previous paragraph). The latter is a result of the fact that STN gives a full carriage return + line feed after each line.
In some places, comments (in bold) have been added to the STN results for explanatory purposes. These will not appear in the normal results that you obtain.
Another useful aid to understanding this document is to recognize the STN prompt (=>). What follows the => will be a command that is to be typed from the keyboard. The command is executed when you press "return." On the line following => (some command) you will see the response that STN gives to that command.
It should be noted that most of this document was created in 1998-99. That is, the STN results are the responses obtained in 1998-99. Since STN is constantly adding new features and updating its operating system and databases, the responses that you get will likely be slightly different. In the main, however, you will find the conceptual approaches presented here are still applicable.
The results of => help are included at various places in the document. These can be fairly long and a bit dry, but they contain much useful information. So read them. Spend some time in LCA seeing what help can give you, it is well worth the effort and will answer many of your questions.
Problems? If you happen to find significant errors in this document, please email the author (rhsmith@wmdc.edu). Please include a description of the problem and a short section of the relevant text or search results.
Finding a specific article (already in hand)
file CA
Getting to STN Express on PowerMac G4's:
Quitting on the PowerMac G4's
With STN Express Version 6.x and 5.x:
The CA Learning File, LCA (Practice here, it is FREE!):
File CA (1967 to present):
Searching for Information (SEARCH command):
Reviewing what has been searched (HISTORY command):
Truncation Wildcards (?, #, !):
Finding Search Terms (EXPAND command):
Obtaining Results from a Set of Records (DISPLAY command):
Formats:
logoff hold:
Working with the Final Search Transcript:
Organizing and Editing Results:Using other Editors (Word Processors)
Editor:
Author Searching:Learning Registry File:
STN Help Desk