Subject Search
Contents


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):

Subject heading
Free-floating subdivision (*)
Keyword
Classification number
Record number

(*) Not available in Children's Subject Headings.

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 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 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.

Note: All ClassWeb search screens include a section of tips and additional options that are kept hidden until you click on the Search tips and options link located under the input boxes.
Tip: Use the Reset button to clear the search screen whenever you want to start a new search.


How to Search
This page describes those aspects of searching that are unique to subject data. For a general introduction to ClassWeb 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 tips and 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--Zaire
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--Advertising
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 preferences. 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.

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 Display
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:

Command and Navigation Buttons

See Searching in ClassWeb for a description of the command and navigation buttons.

Search Results
The results of an index browse and a query differ slightly.

Index Browse Results
If you are browsing an index, the header at the top of the page will display the name of the access point you are using. The results will include a list of index terms followed by a subject heading its cross-references. Here is an example of a structured subject heading browse for the topic "Library science--Anecdotes":

Library science--Anecdotes 
   [Z682.5]
UF  Library science--Anecdotes, facetiae, satire, etc. [Former Heading]

Library science--Anecdotes, facetiae, satire, etc
USE  Library science--Anecdotes
 Library science--Humor

Library science--Awards  (May Subd Geog) 

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":

Library science--Anecdotes 
   [Z682.5]
UF  Library science--Anecdotes, facetiae, satire, etc. [Former Heading]

Library science--Humor 
   [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 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:

ButtonAction
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.


Display Options
To see the display options, click on the Search tips and options link. You can set default values for the following display options by clicking on the preferences link of the main menu:

Display Options
   
   Include subject headings, validation records or both.
    Start with a summary list of index headings.

Your settings may be slightly different depending on your account preferences and current choices. The display options allow you to select:

If you already have search results on your screen and you change any of these options, click on the Redisplay button at the bottom of the page to refresh the screen with your new choices.


Search Options
The search options can be used to force a query to be run instead of an index browse, and to control the way queries are handled. For more information, please refer to Searching in ClassWeb. To see the search options, click on the Search tips and options link. Your screen should now include the following:

Search Options
   Find all matching terms (AND search) or any matching term (OR search).
   Run a browse, basic query or boolean query (requires quotes around your search terms).
    Exact match (don't perform a truncation search that returns alternate word endings).
   Search for subject headings without requiring double dashes between subdivisions.

Your settings may be slightly different depending on your current choices. The search options allow you to select:

If you already have search results on your screen and you change any of these options, you must re-run your search for your new choices to take effect (i.e. click on the Search button after making your selections).


Additional command buttons
In addition to the standard command and navigation buttons at the top of the screen, additional command buttons are displayed at the bottom of the page when you click on the Search tips and options link located under the input boxes. Note that the Redisplay button is only displayed if you have search results on the screen. The additional buttons include:

ButtonAction
Runs a search (same as pressing Enter key). Use after changing search options.
Redisplays the same page of search results using the current display options. Use after changing display options.

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