TOXNET HELP TEXT � HSDB

In the query box, enter one or more terms (e.g., benzene) which describe your search 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.

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, click on the Clear button.

If your query consists of chemicals, TOXNET will, by default (i.e., the radio button "Yes" is 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 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 ("Yes" button selected) 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 ("No" button selected).

Clicking on the Browse the Index button will display a segment of the HSDB index, beginning with the term you enter (e.g., hexachlorobenzene), and let you scan the index alphabetically (or numerically) above or below the original display by clicking on the Up or Down button. For each index term, the system displays the number of HSDB records containing that term. By checking the "Check to Select" box(es) corresponding to the index term(s) of interest and clicking on the Select button, you can search on the selected term(s). You may browse the index to all words, CAS Registry Numbers, or chemical names.

The "Limits" interface boosts search precision over the Basic Search interface by allowing you to specify a particular field or category of fields in which you want your search term to appear. Fields are grouped into categories such as "Substance Identification," "Human Health Effects," etc. The search screen above is an example showing a search for "eye inflammation," in the category "Human Health Effects." Expanding a category by clicking on the "+" will display the individual fields which constitute that category, and by selecting one or more of these, you can perform an even more refined search.

The "Limits" interface also allows you to specify whether you want the terms entered to be searched as exact words, singular and plural forms, or word variants and whether, when multiple terms are entered, the search should be conducted for all the words, any of the words, or as a phrase.

Clicking on any of the cells in this column will take you directly to the search screen for the database selected. "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.

SEARCH RESULTS

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 (e.g., benzene) and there is a match for it in the database, the record for this chemical, referred to as the primary chemical record, 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 the list of records, you can perform 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 vertical series of buttons on the left side of the Search Results page offers a variety of options:

Save Checked Items � This is used to create a subset of your search results. First check the records you want to save, then click on Save Checked Items. The system confirms the number of items you saved and lets you display just these references by clicking on a new button - Display Saved Items - which is added to the series of buttons.

Sort � Sort all or some of the records alphabetically (in ascending or descending order) by substance name.

Details � Summarizes the strategy used by TOXNET to perform your search. This will include your query terms plus any synonyms or CAS Registry Numbers added by the system.

History � Reviews your search session by itemizing your search statements, numbering them sequentially, and listing the number of records retrieved. Clicking on History allows you to view earlier search result sets or combine these sets provided they are within the same database.

Download � You can download all or some of the records in "brief" or "full" formats and select particular categories of information (custom formats).

Modify Search � Return to the Basic Search screen with your search strategy retained. You can make changes or perform a new search at this point.

Basic Search - Return to the Basic Search screen with the query box cleared. You can now enter a new search.

Browse Index � This feature displays a segment of the HSDB index, beginning with the term you enter, and lets you scan the index alphabetically (or numerically) above or below the original display by clicking on the Up or Down button. For each index term, the system displays the number of HSDB records containing that term. By checking the "Check to Select" box(es) corresponding to the index term(s) of interest and clicking on the Select button, you can search on the selected term(s). You may browse the index to all words, CAS Registry Numbers, or chemical names.

Page Navigation - The top and bottom of each Search Results page displays the total number of pages, the current page number, the total number of items, and the items displayed on the current page. You can navigate through multi-page search results by specifying a page number and clicking on the "Go" button or by using the blue arrows to go to the following or preceding page(s).

SELECTED RECORD SCREEN

This screen displays the record for whichever item you selected on the Results Screen. If you searched for a chemical (e.g., benzene) and clicked on the "Primary Record" of the Search Results Screen, you will see the Human Health Effects data displayed, along with a Table of Contents frame on the left. If you clicked 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. From the Table of Contents, you can choose to view the entire HSDB record or portions thereof (by expanding and contracting categories, and checking categories and/or fields) for the chemical you selected.

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.

Next Item - Move forward for a display of the next item (if there is one) in your search retrieval or saved items set.

Previous Item - Move backward for a display of the previous item (if there is one) in your search retrieval or saved items set.

Basic Search - Return to the Basic Search screen with the query box cleared so that you can enter a new search.

Details - Displays a summary of the strategy you specified for your search and synonyms added by the system.

Other Files - Link directly to records in other TOXNET data or bibliographic files (e.g., CCRIS, IRIS, TOXLINE) containing information on your selected chemical.

Modify Search - Return to the Basic Search screen with your search strategy retained. You can make changes or perform a new search at this point.

Download - You can download the selected record in "full" format and select particular categories of information (custom formats).

Limits - Boosts search precision over the Basic Search interface by allowing you to specify a particular field or category of fields in which you want your search term to appear.

Browse Index - This feature displays a segment of the HSDB index, beginning with the term you enter, and lets you scan the index alphabetically (or numerically) above or below the original display by clicking on the Up or Down button. For each index term, the system displays the number of HSDB records containing that term. By checking the "Check to Select" box(es) corresponding to the index term(s) of interest and clicking on the Select button, you can search on the selected term(s). You may browse the index to all words, CAS Registry Numbers, or chemical names.

HOW THE SYSTEM SEARCHES FOR AND DISPLAYS RECORDS

TOXNET searches for your terms, in singular and plural form, throughout all records unless you specify particular fields or restrict the form of your terms via the "Limits" interface. The system will automatically look for synonyms and CAS Registry Numbers of chemicals unless you choose to disable this feature.

Multiple Terms

If you search on multiple 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. These records will be followed by records in which the terms appear 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

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.

Best Sections

In searching for a particular chemical, say "benzene," your retrieval may include chemical records in addition to the initial matching chemical record, called the "primary" record. These additional records appear if they 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 in which Best Sections would occur is in searching for a subject, say "hypothermia." 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 "hypothermia" appears with the greatest frequency.

HSDB CONTENT AND FIELD MNEMONICS

HSDB contains over 4500 chemical records, each of which can have as many as 150 or so fields of data. Its broad scope covers human and animal toxicity, safety and handling, environmental fate, and more. HSDB data undergo a high level of peer review by the HSDB Scientific Review Panel. Not every chemical will contain data in each field. A list of database fields and corresponding mnemonics may be found at HSDB Fields Description.

ADVANCED SEARCHING FEATURES

Users seeking a finer degree of precision in retrieval than available through either TOXNET's standard Basic Search screen or Limits option may want to consider formulating searches through the use of field qualifiers and/or 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 field qualifiers and/or Boolean logic.

Field Qualifying is a method whereby you can specify the particular field in which you want your term searched. Thus, if you are looking for HSDB chemical records which specifically address the kidney in humans, you might want to limit (or qualify) your search by specifying that only the Human Toxicity Excerpts field (htox) be searched for the word "kidney." The format for field qualifying consists of the search term followed by the field mnemonic in brackets. Thus, continuing with this example, to look for records where "kidney" appears in the "htox" field, you would enter "kidney [htox]." The Chemical Name field mnemonic is "na." A search for the exact chemical name "chlorine" in the HSDB file, for example, would be formulated as "chlorine [na]." Be advised that when you qualify a search by data field mnemonic, you are instructing the TOXNET system to search precisely the field you have specified. If the search term does not appear in the qualified field, an error message stating that "No records were found for the search" will be generated. A list of database fields and corresponding mnemonics for HSDB may be found at HSDB Fields Description.

Boolean Searching utilizes the logical operators OR, AND, NOT. It is a means of limiting your search of two or more terms to criteria you specify, and is often used in conjunction with field qualifying, described above. Logical operators must appear in upper case. Searches containing combinations of these operators are processed with ANDs taking precedence, followed by NOTs, and then followed by ORs. This default precedence may be overridden with the use of parentheses, which may also be nested (i.e., parentheses within parentheses).

Truncation - The asterisk (*) may be freely used as a truncation symbol standing for any number of characters. Searching in HSDB for "spin* [htox]" will retrieve records with words such as spine, spinal, spino, and spinally in the Human Toxicity Excerpts field. Truncation may be used with or without field qualifying/Boolean searching.

Phrase Searching - In phrase searching, quotation marks ("�") are included as part of the search strategy and are used to search for two or more terms exactly the way they are entered. In HSDB, you might want to search for records containing the phrase "liver failure" in the Human Toxicity Excerpts field. This would be accomplished by entering the phrase and the appropriate field designator as follows: "liver failure" [htox]. As another example, a search for kappa receptors in the Mechanism of Action field would be entered as "kappa receptors" [actn]. Phrase searching may be used with or without field qualifying/Boolean searching.

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