- Introduction
- Main Menu
- Search Display
- Search Options
- How to Search
- Searching for Subdivisions
- Access Points
- Search Results
- Display Options
Introduction
The subject search system locates and displays LC Subject Headings, Genre/Form
Headings and Children's Subject Headings, each stored and accessed separately via
different main menu selections. They all share the following access points (except
that there are no free-floating subdivisions in the Children's Subject Headings):
Free-floating subdivision (*)
Unstructured heading
Unstructured subdivision (*)
Keyword
Classification number
Record number
(*) Not available in Children's Subject Headings.
For single access point browsing, the subject browser is a convenient and fast way to select between different access points and locate records.
Main Menu
Choose a subject search page from the main menu by clicking on the appropriate Search link.
Alternately, use one of the Browse links to browse a single access point.
The LC subject search page looks like this:
In general, with the exception of the Keyword access point, when you enter your search criteria into only one of the input boxes and press Enter (or click on the Search button), you will be performing an index browse. The records will be returned in the sorting order for that access point. When browsing an index, you can view all of the records in a database and not just those that match your initial search term. If you prefer, you can force a query to be run by checking either the basic query or boolean query search options before submitting your search request. See below for more information on changing your search options.
If you input one or more words into the Keyword box or input values into any two or more access points or check either the basic query or boolean query search options, ClassWeb Plus will run a query to locate all records that meet your criteria. While browse results are returned instantly, a real query may take a few seconds (or even minutes, depending on the search). Also, query results are not returned in any particular sequence, although they tend to be in record number order.
ClassWeb Plus supports truncation searching (you just input a partial search term), boolean (AND, OR and NOT) and mathematical (less than, greater than, etc.) operations, and wild-card characters (? matches any single character and * matches multiple characters). In addition, all keyword access points support phrase and proximity searches.
- After running a search and results are displayed on your screen, click on the Refine search button to change your query criteria or the New search button to clear your criteria and begin again.
- To switch to the subject browser from the search screen, click on the Tools icon (which looks like a gear) on the right side of the top navigation bar and select Browse.
Search Options
The Search options link on the seach screen provides options that control how searches are run and how the results are
displayed. For more information on how search options affect a query, refer to
Searching in ClassWeb Plus.
Clicking on the Search options link on the subject search screen will change the page like this:
- The number of records to return per page.
- The amount of hierarchy to display with each record.
- Whether to include validation records. Validation records are subject heading authority records that were created solely for the purpose of allowing for machine validation of commonly used subject strings consisting of authorized headings combined with free-floating subdivisions. For more information, please see the CDS announcement on this topic.
- Whether to start with a summary list of index headings. With this box checked, a summary list of index headings is returned instead of a full subject display. By starting with a summary list, you can scan the screen for the item you are interested in and click on that link to display its full listing.
How to Search
This page describes those aspects of searching that are unique to subject data. For a
general introduction to ClassWeb Plus searching, please refer to the following help pages:
Searching for Subdivisions
Both the Subject heading and Free-floating subdivision access points
include headings with one or more subdivisions. To locate these headings you have a choice
as to whether or not you have to input double dashes (--) between each subdivision. You make
this choice with the search option that reads: Search for subject headings without requiring
double dashes between subdivisions. Search options are displayed by clicking on the
Search options link located under the input boxes.
When browsing the Subject heading and Free-floating subdivision access points, the order that the records are returned changes slightly depending on whether you have selected the above option. If you don't check the box, the records are returned in standard LCSH Subject Heading print product order. That is, all of a subject's subdivisions are displayed before moving on to the next subject -- i.e. they will be in hierarchical order. If you check the option so that double dashes are not required in your headings, the headings and their subdivisions will be in simple dictionary order -- all of a subject's subdivisions will not necessarily be printed before moving onto the next subject.
Take, for example, the subject term of railroads. If you don't check the above option and use the subject heading access point, you have to navigate past all of the subdivisions of railroads before you reach Railroads, Aerial (a different subject heading with no subdivision). The sequence looks like this (only the headings have been reproduced here and not the full content):
Railroads--Zambia
Railroads--Zimbabwe
Railroads, Aerial
Railroads and state (May Subd Geog)
Railroads and state--United States
Railroads, Atmospheric (May Subd Geog)
Alternately, by selecting the option to avoid using dashes, the term Railroads, Aerial follows Railroads--Advertising (instead of Railroads--Zimbabwe as in the previous example). The sequence looks like this:
Railroads, Aerial
Railroads--Africa, East
Railroads--Africa, Northeast
Railroads--Air-brakes
Railroads--Airspace utilization (May Subd Geog)
Railroads and state (May Subd Geog)
Railroads and state--United States
If you generally prefer to not have to input dashes when searching subject headings, you can set this option in your account settings. This way, you won't have to keep setting this option on the search screen.
Access Points
The access points for subject searching include:
Subject heading
This access point includes all subject headings and their tracings (links to other subjects).
They are sorted in traditional LCSH or dictionary order depending on whether the no dashes
option has been selected (see above for more details).
This access point searches the following fields:
100, 110, 111, 130, 150, 151, 155,
400, 410, 411, 430, 450, 451, 455,
500, 510, 511, 530, 550, 551 and 555
From each of those fields, the following subfields are extracted for the subject heading:
a-h and j-u
And the following subfields are extracted for the subdivision:
v, x, y and z
Free-floating subdivision
This access point includes all free-floating subdivision fields and their tracings (links to
other subdivisions). They are sorted in traditional LCSH or dictionary order depending on
whether the no dashes option has been selected (see above
for more details). Note: There are no free-floating subdivisions for the children's
subject headings.
This access point searches the following fields:
180, 181, 182, 185,
480, 481, 482, 485,
580, 581, 582 and 585.
Along with the following subfields:
v, x, y and z
Keyword
Use this access point to search for words and phrases that might be found throughout in a record.
There is a separate help page that documents how keyword
searching is implemented in ClassWeb Plus.
This access point includes all words and phrases found in subfields a - z of the following fields in a record.
1xx, 2xx, 3xx, 4xx, 5xx and 680
Classification number
This access point contains the classification number from each record that has such a number.
Not all subject headings have a classification number assigned to them.
The classification number access point searches the following fields:
053/a and 053/b
Record Number
This access point searches the 001 field – Control Number – from each
LC subject heading record. This is the same value as the 010 field – Library
of Congress Control Number – in these records.
Search Results
Search results are displayed a page at a time, with twenty-five or more records per page. You can change the
number of records that are returned in any of the following ways:
- To change the number for the current web browser tab or window click on the Search options link when inputting your seach. Use the drop-down list immediately under Display Options to choose a different number and run the search again.
- To change the default number of records displayed by all ClassWeb Plus screens for your account (this will affect everyone who logs in to your account), modify your account settings with the Settings link found on the drop-down menu at the top of every page (requires administrative password).
The results of an index browse and a query differ slightly.
Index Browse Results
When you are browsing a single index, the results will look something like this (in this case, the term "Library science--Anecdotes" was typed
into the Subject heading field):
Some subject heading records have a LC classification number associated with them. These are
displayed in square brackets below the heading. Clicking on a classification number will launch
the classification browser in a separate window for that number. Clicking on any of the cross
references will take you to those subject headings. Finally, each established heading is followed
by a small white button ( )
that displays a drop-down menu of additinal links for that record (see
below).
Query Results
For a query, the header will display the query number and the number of records that matched your
criteria. The results will include any matching subject heading records and their content. Here
is an example of a structured subject heading query for the topic
"Library science--Anecdotes":
[Z682.5]
| UF | Library science--Anecdotes, facetiae, satire, etc. [Former Heading] |
[Z682.5]
| UF | Library science--Anecdotes, facetiae, satire, etc. [Former Heading] |
These results are from query number 1 where 2 records were found. Since this query was run with truncation support enabled (the default for all ClassWeb Plus queries) the second record was found because its Use for reference was a partial match for the search term. If the Exact match option had been choosen, only one record would have been found.
As with index browsing, query results can include cross references and classification number
links. Any established headings will be followed by a small white button (
) that displays a drop-down
menu of additinal links for that record (see below).
Record Links
Every subject record in the list of search results is followed by a little white button
( ) which,
when clicked, displays a drop-down menu of additional links. See above
for search display examples. The links can include:
| Item | Action |
|---|---|
| Dewey correlation | Displays Dewey classification numbers that are most often used with this LC subject heading. Note: If this feature is of no interest to you, you can remove this link from the drop-down menu by changing your account preferences. |
| LC class correlation | Displays LC classification numbers that are most often used with this subject heading. |
| MARC record | Displays this subject heading record with its MARC tags. |