Searching the Scientific Literature
"Publications are at once the end-product of scientific research and the raw material for future research." (A.F Spillhaus)
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Initial Planning: Approaches to Searching: |
REASONS FOR SEARCHING
Scientific research is a cumulative process with present research building upon a knowledgebase of information that resides in the scientific literature.There are a variety of reasons why one may need to search, find and use scientific literature. Each reason requires a slightly different process and the use of a somewhat different set of information tools.
- Current Awareness - keeping current and informed about new literature and current progress in a specific area of interest. This is done in a number of ways, both informally in communications with colleagues and more formally through sources such as those listed in Current Awareness in the Sciences. You can also use Databases available to HSU students and faculty to do a subject search of current literature added to a database. Some allow you to save a search profile that can be run periodically against new records added to the database.
- Practical or Everyday Needs - specific information needed for experimental work or application of scientific understanding. It may be collaborating data, a method or technique, the construction of experimental apparatus, a mathematical equation, an explanation for an observed phenomenon, development of a management plan for an endangered species or other similar needs. Locating the information needed in the daily work of scientific research can take a great of time. Informal communication with colleagues is a major source for meeting these needs. Print and Internet resources referenced in the scientific Research Guides are also important sources for meeting the everyday needs of scientists.
- Exhaustive Research - need to identify "all" relevant information on a specific topic. This typically occurs when a researcher begins work on a new investigation or in preparation for a formal publication. Indexes and catalogs are typically used to identify scientific literature on a specific topic.
FOCUSING YOUR SEARCH--primary or secondary scientific literature
One of the first steps in developing a search strategy is deciding where to initially focus your literature search--primary or secondary literature.
- Publications that report the results of original scientific research constitute the primary literature of the sciences. Examples include journal papers, conference papers, monographic series, technical reports, and theses and dissertations.
- Publications that synthesize and condense what is known on specific topics constitute the secondary literature. These include reviews, monographs, textbooks, treatises, handbooks and manuals. Because secondary literature in the sciences frequently provides a broader context and contains references to key primary literature this is often a good place to start. Scholarly books can be used for gaining knowledge in a particular subject area, learning about the historical development of a topic and finding out the names of key researchers.
To search for books and government documents that are part of the secondary literature use the HSU Library Catalog, the catalogs of Other Libraries and the U.S. Government Publications Monthly Catalog. In addition many of the Research Guides developed by HSU librarians list important secondary reference tools in the HSU Library and on the Internet that can be used as starting points for research. Sometimes an older bibliography will comprehensively cover earlier primary literature.
To directly search for primary literature use indexes that are listed under Articles and Databases on the Library's web page. Every scientific discipline has at least one index to its research literature.
SUBJECT SEARCHING
This method involves using subject keywords to search indexes for primary literature and catalogs for secondary literature. To effectively conduct a subject search you should first develop a subject search strategy and then think about how you will enter your search in an index or catalog.
- Develop a subject search strategy. Start by constructing a search
strategy as presented in the Search Strategy
Worksheet. Briefly this worksheet includes the following four steps:
- Summarize your topic in one or two sentences.
- Identify the unique ideas or concepts associated with your topic.
A literature search topic typically has two or three unique concepts.
In the sciences, these concepts commonly fall into one of these categories:
subject, taxonomic, geographic, time, habitat, life stage, or chemical
substance.
- Choose appropriate keywords for each concept. Each concept
usually can be described using several specific keywords. These keywords
can be developed in several ways - your personal knowledge of the
topic, suggestions of others, or background reading that you do in
secondary sources. In making a list of keywords consider the following:
- Many indexes and catalogs use "controlled" keywords that come from associated thesauri or lists of keywords and which are assigned by indexers to every citation. They bring together similar ideas under one standardized word or phrase that may be described in the discipline literature by several different keywords.
- In developing keyword lists consider possible hierarchical relationships within a particular concept. For example, with a taxonomic concept are you only interested in locating research on a particular species or is a broader taxonomic classification also of interest?
- As you list keywords examine each one to see if it can be beneficially truncated. A root word can be truncated with a wildcard symbol (e.g., *, #, ?, +) to retrieve its variant forms. This is especially true for single and plural variants of a word. For example, prevent* will retrieve prevention, prevented, or prevents. To find the correct wild card symbol, consult the help section in the database you will be using.
- For taxonomic concepts use both common and scientific names of organisms when appropriate. Using both will normally increase the number of citations retrieved.
- Establish the relationship between each keyword and concept. AND, OR, and NOT Boolean operators can be used to connect together every keyword and concept in a search statement. Nesting must be used in some cases to indicate the correct relationships between Boolean operators.
- Summarize your topic in one or two sentences.
- Strategize how to enter your search in indexes and catalogs.
- Concepts within a topic are often a mixture of specific and broad
ideas. A useful approach is to identify the most specific concept
and search that one first. If this initial search retrieves only a
few references, just browse through them and identify the ones relevant
to your topic. If the search retrieves many references, add another
concept using the "and" connector to decrease your results.
- Use "controlled" keywords as described above. If you do not know
what "controlled" keywords to use, conduct an initial search using
the keyword(s) you have. In reviewing the search results look for
"controlled" keywords, often called descriptors or subject headings,
which commonly appear as part of each citation (see sample).
Re-enter your search adding these "controlled" keywords to your existing
keywords.
- Use a "building block" approach to searching if the database you
are searching allows for it. Enter each of your concepts individually
by ORing together the list of synonymous keywords you have
created, e.g., prevent* or avoid* or deterr*. After each of your concepts
has been entered use the database "Search History" feature, if available,
to AND together each of the concepts. Employing this approach
allows you to:
- add new keywords you have identified to an existing concept, e.g., concept 1 or avert* (new keyword)
- try different concept combinations using the AND connector,
e.g.,
concept 1 and concept 2 and concept 3
concept 1 and concept 3
concept 3 and concept 2
- Searching is a dynamic process. As you proceed in your literature search, and as your personal knowledge increases, your list of keywords is likely to grow and/or be refined.
- Concepts within a topic are often a mixture of specific and broad
ideas. A useful approach is to identify the most specific concept
and search that one first. If this initial search retrieves only a
few references, just browse through them and identify the ones relevant
to your topic. If the search retrieves many references, add another
concept using the "and" connector to decrease your results.
CITATION SEARCHING
As part of the scientific research process reference is made within current publications to earlier related research or to techniques which have been utilized in the current research. These references are typically cited within the text of scientific publications and listed in a concluding "Bibliography" or "Literature Cited" section. The average scientific paper contains eleven references to related research.
Starting with at least one initial citation a bibliography of both older and newer research related to your topic can be created without much effort. These initial references may come from several possible sources:
- Identified through subject searching of indexes and catalogs
- Derived from your personal knowledge of the literature on a specific topic
- Gleaned from reference books such as subject encyclopedias, treatises, bibliographies, and annual reviews
- Received from someone who has specific knowledge on the topic.
- To find older references.
To work BACKWARD in time use the "Bibliography" or "Literature Cited" sections of publications already in hand. Just look up appropriate references cited in these publications and then continue to follow up additional references that you find in older papers. Depending upon the extent of your information needs this process can be repeated until the point is reached when no additional older references are located.
- To find newer references.
Several databases allow you to work FORWARD in time. The results of your search in these databases will be a bibliography of more recent papers that have cited your original older reference. You should start with SciSearch/Science Citation Index and then Google Scholar.
- SciSearch/Science Citation Index (other libraries may carry the Web of Science version) indexes cited literature that has been included in the "Literature Cited" or "Bibliography" of papers found in 4,500 journals from 1974 to the present. Enter an older reference in the correct format to find more recent papers that have cited your original reference. (Note: direct access to this database is limited to HSU faculty and graduate students; all others must search this database through a librarian.
- Annual Reviews includes a list of articles which have cited each review paper and the ability to set up a search alert for new articles that have cited a review paper
- BioOne (HSU users only) includes a link for more recent "Articles Citing This Article" in BioOne and other CrossRef compatible databases.
- BioOne Abstracts and Indexes (HSU users only) includes "Cited by" links to both indexed articles and to each article's cited references. The citing references are taken from other CSA environmental indexes.
- Blackwell Synergy lists other Blackwell journal papers that have cited a specific article in the database. You can also set up an alert to notify you when that same article is cited by new Blackwell journal articles.
- Chemical Abstracts Online (HSU users only) allows you to use the "Citing References" button to find more recent references in the database or in SciSearch that have cited your reference.
- CINAHL (HSU users only) includes a "Times Cited in this Database" link for more recent nursing and health articles in the database that have cited a reference.
- CiteSeer is a citation based index to computer and information science literature.
- Google Scholar search results include a "Cited by...." link that lists all sources in Google Scholar that have cited each reference. For additional information on Google Scholar content and operation see How to Use Google Scholar & the HSU Library.
- Highwire Press includes a "Cited by other online articles" option that allows you to find more recent Highwire Press online articles that have cited it. Also includes an option to "Alert me if this article is cited" by newer Highwire Press article additions.
- PsycINFO (HSU users only) includes a "Cited By" link for more recent citing references. The article bibliography also includes "Cited By" links.
- ScienceDirect (HSU users only) allows you to find more recent papers added to the ScienceDirect database or the Scopus database that have cited an included article. ScienceDirect includes fulltext articles from over 1800 journals plus references from the Medline database. There is also an option to establish a "Citation Alert" to receive automatic notification of new papers added to the database that have cited your reference.