In the long empty query
box, enter one or more terms
(e.g., benzene) which
describe your search needs topic.�
These may be any combination of words, chemical names, and numbers,
including Chemical Abstracts Services (CAS) Registry Numbers (RN).� Common �stop words� such as �a,� �an,�
�for,� �the,� and �it,� although you may enter them, will not be searched.
Examples of search terms:
-
acetone
-
vinyl chloride
-
67-64-1
-
75-01-4
-
brain
-
dna adducts
-
skin tumors in mice
-
biomarkers
-
aflatoxin b1
The term(s) entered will be
searched for in all IRIS fields.
The search will be initiated
when you click the �Search� button.� To erase your search term(s) and start over with a blank query box again, click on
the �Clear�
button.
If your query consists of
chemicals, TOXNET will, by default (i.e., the radio button �Yes� is marked selected), expand your search by adding synonyms and
CAS Registry Numbers.� Thus, if you
enter �perchloroethylene,� the system will add the CAS RN 127-18-4 and synonyms such as �tetrachloroethylene� and �tetrachloroethene.�� You have the option to turn off this feature
by marking selecting the button �No.�� This will result in a search only for the
exact word(s) you entered.� In the
example above, the system would then look only for the word
�perchloroethylene.��
For typical queries, it is
suggested that you leave the synonym searching feature on (leave �Yes� button markedselected) in order to maximize
retrieval.� On the other hand, if you were searching
specifically for a brand name product, say �tylenol,� and were interested only in records that
mentioned the chemical with that name, you might want to turn off synonym
searching (mark �No� button selected).
Clicking on the Browse the Index button willThis feature displays
a segment of the IRIS index,
beginning with the term you enter (e.g., hexachlorobenzene), and lets
you scan the index alphabetically (or numerically) above or below the original
display by clicking on the �UP�Up or �DOWN�Down button.� For each index term, the system displays Tthe number of IRIS
records containing each of thethat terms is displayed.� By checking the �Check to Select� box(es) nextcorresponding to the index term(s) of interest and clicking on the �Check to Select�
button, you can search on these selected term(s).�
You may browse the index to all words, CAS Registry Numbers, or chemical
names.
Clicking on any of the cells
in this column will take you directly to the search screen for the database listedselected.� �Multi-databases� offers simultaneous
searching of HSDB, CCRIS, IRIS, and GENE-TOX.�
The information icon (�i�) next to each database provides a brief
description of it, with links to a more detailed Fact Sheet and a sample
record.�
You may also visit
additional NLM Web-Based Resources:
����������� DIRLINE � Directory andof health and scientific
organizations.
����������� Tox Web Links � Links to additonaladditional toxicology wWeb sites.
����������� MEDLINEplus Tox/Env
Health � Consumer health information on toxicology and environmental Hhealth topics.
����������� PubMed � Access to the MEDLINE database of biomedical
literature.
����������� NLM Gateway � Searches across multiple NLM databases.
����������� Locatorplus � NLM�s
online catalog of books, audiovisuals, and journals.
Or Support Pages:
����������� Help � Page specific dDetailed documentation, such as what you are now reading now, about searching
TOXNET.
����������� Fact Sheet � ForProvides an expanded description of IRIS.
����������� Sample Record � A look at a sample IRIS record.
����������� EPA Disclaimer � Brief EPA account of IRIS data, including links to
further information.
�����������
Your initial retrieval is
displayed as a list of chemical names, highlighted in blue and underlined, and
their CAS Registry Numbers.� If your
search was for a chemical and there is a match for it in the database, the
record for this chemical, referred to as the primary chemical record (e.g., benzene), will
display first, followed by a list of other chemical records which also contain
some mention of the chemical you entered.�
This latter list of chemicals is displayed according to a Relevancy
Ranking algorithm.� Clicking directly on any of
the items will provide a display of the Selected Record Screen, containing all
the data, for that item.
If your query consists of
words that are not chemical terms, this same Relevancy Ranking algorithm
determines the order of display of all your search results.
By checking one or more of
the numbered boxes to the left of eachthe list of records, you can perform later operations, such as downloading, on these selections at a later time.
You can alter your search,
if you choose, directly in the query box which reappears on this page with your
search terms.� Alternately, you can use
the Modify Search
button, described below.
The sidebar vertical series of buttons on
the left side of the Search
Results page offers a variety of options:
The top and bottom of each
Search Results page always displays the total number of items retrieved and the
range of items displayed on the current page, and, depending on the number of
search results, the current page number and the total number of pages. You can
navigate through multi-page search results either by specifying a page number
and pushingclicking on the �Go�
button or by using the small blue arrows to go
to the following or preceding page(s).
This screen displays the
record for whichever item you selected on the Search Results screen.� If you search for a chemical (e.g., benzene) and then click
on the �Primary Record� of the Search Results screen, you will see the entire
record, along with a Table of Contents frame on the left.� If you click on a different chemical record,
the sections of the record best matching your query terms will be displayed
(see Best Sections), again, with an accompanying Table of Contents frame.� From the Table of Contents, you can then
select to view portions of the record by expanding and contracting categories
and selecting specific categories and/or fields of the record.
If your original search was
for a term other than a chemical, any chemical record you click on from the
Search Results screen will result in a �Best Sections� display.
The search term(s) you
entered, as well as synonyms (if you selected to search for them), will all be highlighted
in red wherever they appear in the text of the selected chemical record.
Across the top of the screen
is a header
series of
buttons with more options:
TOXNET searches for your
terms, in singular and plural form, throughout allthe records unless you specify
particular fields.� The system will
automatically look for synonyms and CAS Registry Numbers of chemicals unless
you choose to disable this feature.
If
you search on multiple query terms, and each record retrieved
contains all the terms you entered, the system will first display those records
in which all the terms appear in the same section of the record.� This These records will be followed by records where in which the terms appear
anywhere in
different sections of the record.� If a multiple-term search fails to retrieve
any records containing all the terms entered, the system will display the
following message: �No records were found which contain all of the search
words.� The following records contain at
least one of the words.�
Relevancy
ranking attempts to determine which documents are most pertinent to the search,
and to place the most relevant documents first in the list of returned
documents.� The ranking is based upon
the number of individual search terms occurring in a document, the number of
times each search term occurs in a document, its rarity within the database,
and the nearness of search terms to each other.� Documents containing combinations of search words tend to be ranked higher
than documents having isolated occurrences of the words.
In
searching for a particular chemical, say �benzene,� your retrieval may include chemical records
in addition of to the initial matching chemical record,
called the �primary� record.� These other additional records might appear
if they otherwise
contain the word �benzene.��
This might occur, for example, if the chemical is a metabolite of
benzene, interacts with benzene, or has been tested along with benzene in a
toxicity study.�
Clicking
on any of these non-primary chemicals on the Search Results screen will display
the Best Sections, those where the chemical search term appears with greatest
frequency.� The term searched appears
highlighted in red.
Another
situation where in which Best Sections would occur is in
searching for a subject, say �DNA.�� In
this case, clicking on any of the chemicals in the Search Results screen will
display the Best Sections, i.e., the sections of the records where the word
�DNA� appears with the greatest frequency.�
IRIS contains data in
support of human health risk assessment.�
It is compiled by the U.S. Environmental Protection Agency (EPA) and
contains over 600 chemical records.�
IRIS data, focusing on hazard identification and dose-response
assessment, is reviewed by work groups of EPA scientists and represents EPA
consensus.� Among the key data provided
in IRIS are EPA carcinogen classifications, unit risks, slope factors, oral
reference doses, and inhalation reference concentrations.
Users seeking a finer degree
of precision in retrieval than available through TOXNET�s standard Basic Search
screen may want to consider formulating searches through the use of Boolean
logic.
Users seeking a finer degree
of precision in retrieval than available through TOXNET�s standard relevancy
ranking methodology may want to consider formulating searches through the use
of bBoolean logic.
TOXNET is best viewed with
Internet Explorer 4.0 or Netscape 4.0 or higher versions, for either PC or Mac.