# Chemical Information Sources/Guides
## Introduction: Search Strategies and Guides

A SEARCH STRATEGY is a map of a course of action in searching that should result in finding an answer to a chemical information problem. It could involve using library, free internet, and/or commercial database resources. A search strategy includes such tasks as:
* identifying the main concepts and other parameters for the search, including time period of interest, types of documents to be retrieved, and other factors (e.g. immediacy of the need for the answer)
* drawing up a list of terms and other search keys to be used, such as chemical structures, authors' names, chemical names, etc.
* deciding what sources are most likely to have the answers
* searching the selected sources until the answer is found or you are satisfied that no answer can be found in the available resources.
For the third bullet point, the works described in this chapter will help in making appropriate choices. Works that help you decide what secondary or primary tools to use, or works that actually help you use those tools, are referred to as GUIDES, sometimes called TERTIARY tools. These may help:
* find relevant tools to solve an information problem, and
* learn how to use those tools.
Guides are found as printed books, directories of databases, directories of resources on the Internet, "how-to" manuals that accompany software or databases, and in several other formats, including online help files.

## Finding Guides
### Online Guides

With the proliferation of Web-based resources in recent years, a variety of both free and subscription-based resources are widely available. Academic institutions usually have extensive and carefully prepared publicly available guides to both types of resources. These are usually maintained by subject specialist librarians and are found on the web page of the library under links named resource, research, or subject guides. However, access to subscription-based resources is limited to those affiliated with said institution and possibly on-site walk-in use. Nearly every major chemistry library maintains a number of excellent guides. For one example, look at University of Pennsylvania's chemistry & chemical engineering research guides covering both print and online sources.
Professional organizations and societies (such as the American Chemical Society or the Royal Society of Chemistry) also have some resources freely available. Private companies often have internal databases and resources, and requisite guides to accompany them. Often, commercial databases will have some documentation publicly available, and more information can often be found in academic guides as well. A list of guides has been associated with this wikibook.
As a part of this work, a guide to chemistry resources on the Internet has been compiled. It is recommended to check with your local institution to see what subscription-based resources are available, and what in-house guides are available. Resources for some Web-based commercial databases are included in the Chemistry Databases on the Web subsection of this work. Finally, chemical information teaching resources are being deposited in XCITR, a cooperative site sponsored by the American and German Chemical Societies and hosted by the Royal Society of Chemistry.

### Print Guides

Print guides are still available and may be of use if Web-based guides are insufficient or unavailable. It is important to remember that online databases are still a relatively recent development, whereas the printed archive of chemical knowledge extends back several centuries. There is still much historical chemical literature not available full-text on the Web, or indexed in databases.
Most recently published is the 2013 book, Chemical Information for Chemists: A Primer (Royal Society of Chemistry), edited by Judith Currano and Dana L. Roth. The classic work of this type was Mellon's Chemical Publications which came out in five editions between 1928 and . Two more recent printed guides is Andrew Poss's "Handbook for Organic Chemists" (Chemical Publishing Company, 2000) and Robert E. Maizell's "to Find Chemical Information: A Guide for Practicing Chemists, Educators, and Students (3rd edition)" (John Wiley & Sons, 1998). The "Search Orientation Table" in Poss's work relates questions to appropriate sources. You will find there the tables of contents of standard printed works such as the treatise Comprehensive Organic Chemistry.

## The Difference Between Database Producers, Vendors and Search Platforms, and Guides to Using Them
### Definitions

VENDORS are commercial entities that lease database content from DATABASE PRODUCERS, mount them on SEARCH PLATFORMS to provide a unified, common search interface, and then sell access to the content through the interface. Usually the mode of delivery is the Internet, or in some large companies, an internally maintained intranet. It is important to note that the same database may be available on several different vendors' systems. Some examples of this include the National Library of Medicine's MEDLINE database, which is accessible through the SciFinder, PubMed, and Web of Science platforms. The CAPlus database is available through the SciFinder and STN platforms. Sometimes, different components of the database may only be accessible via certain platforms, such as available time periods and search conventions/syntax for searching information in specific data fields in the records. For example, some fields in CAS databases are searchable only in STN International.
Note that the same entity may be both a database producer and a vendor, creating a platform by which to access to its own databases as well as those of other producers. For example, the vendor Thompson Reuters' Web of Knowledge platform provides access to its own Science Citation Index database as well as MEDLINE (among others).
Journal publishers likewise may also be a database producer and a vendor. Individual journal publishers, such as Elsevier and the Royal Society of Chemistry, often maintain sophisticated search interfaces for the content they publish including deep archives going back decades or even centuries. Although these publisher sites are both powerful and useful, the searcher should always remember that typically only content from that single publisher is accessible, regardless of how large that one publisher might be. Elsevier, for example, provides content from the thousands of journals and books it publishes on its ScienceDirect platform, but neither American Chemical Society or Royal Society of Chemistry journal content is available through their search system. However, Elsevier also produces the Scopus database and platform, which indexes content from a variety of publishers.

### Search Platforms and Interfaces

Often a search platform provides multiple versions of its search interface or search query screen such as a Google-like single box quick search, a basic search with multiple boxes whereby multiple terms from different fields can be combined using Boolean logic, and an advanced or expert query screen with the ability to build extensive search queries using highly precise field and syntax codes.
Most vendors have extensive documentation online regarding the database structure, content, and search tips/syntax. Especially helpful are the commonly available short training videos that highlight specific tasks and features. These links are often under Support, Help, or Training sections of the vendor's web site.

### Database Summary Sheets

A particular type of guide is the DATABASE SUMMARY SHEETS provided by the vendors or producers of online databases. The vendor Dialog Information Services makes available their "bluesheet" database summary sheets. STN's database summary sheets are also available as Internet files. Look at the database summary sheets for the LCA (Chemical Abstracts Learning File on STN) and LREGISTRY (Chemical Abstracts chemical dictionary learning file on STN). Note the different search and display possibilities that are possible with these files and how the summary sheets help you select the right way to enter the search if you were using the native command language of the STN system, STN Messenger. Today, most chemical searchers don't have to know anything about the STN command language because Chemical Abstracts Service's SciFinder product does much of that work for you behind the scenes. Nevertheless, some examples of the STN Messenger command language searches are included throughout this work in order to demonstrate the power of command-language searching. Command line searching on the vendor systems is still in demand in industry because it allows experienced online searchers to be much more precise with their search strategies.

### Multi-Database Platform Searches

Another approach to selecting a database is to let the commercial vendor's search system analyze which databases among their offerings have information relevant to your search. Dialog Information's DIALINDEX identifies which DIALOG files have information on a given topic; INFODEX is an online index to the contents of more than 30 databases on the Chemical Information System, a collection of environmentally-oriented databases. The corresponding type of search on STN would be done with the STNindex feature. The STNGuide file is a database of STN Summary Sheets. It can assist in selecting the proper database to search.

## Summary

The literature of chemistry is so huge that it can be a bewildering task to decide just where to start. The guides that have been developed over the years can remove most of the uncertainty about the best path to find an answer to a chemical question. One thing to keep in mind, however, is that some chemical questions will not have answers in the literature. It is up to the searcher to decide how much time and effort should be used in the pursuit of an answer. A well thought-out strategy, based on the information gleaned from the guides (and, if possible, consultation with a local chemical information specialist) can make the search much more fruitful.
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