How to utilize full-text search
updated on
by Service Planning Division
1. About full text search
Full-text search enables the searching of titles, tables of contents, text, captions of illustrations in books and magazines, and is useful in finding content not shown in titles or tables of contents. It is also possible, however, that it will retrieve unrelated information. Thus, to obtain useful results, it is essential to understand the characteristics of the full-text search function before using it.
This article focuses on how best to utilize the full-text search functionality offered by the NDL's web services.
2. Full-text searches of the NDL Digital Collections
The NDL Digital Collections offers full-text searches for many materials.
Full-text searches are available for the follows materials:
- Full text embedded in electronic files such as electronic books, electronic magazines, and doctoral dissertations collected in electronic form.
- Full text of digitized materials (parts of books, magazines, official gazettes, etc.) acquired via optical character recognition (OCR)
*Full text acquired via OCR is not proofread and might include incorrectly recognized text. Also, recently acquired materials and other materials may not yet have OCR text available.
Reference: Materials Available for Full-Text Searches in the NDL Digital Collections
Not all materials held by the National Diet Library are included in the NDL Digital Collections. For materials included in the NDL Digital Collections, please see About the NDL Digital Collections 4. Overview of the materials provided via this system.
Though included in the NDL Digital Collections, some materials, such as collections of tanka and haiku, do not display snippets not to be displaying an entire copyrighted-work in snippet form. Dictionaries and the Japanese Company Handbook are the same because snippets alone are sufficient to use.
2-1. Browsing the NDL Digital Collections
The content of books and magazines that appear in NDL Digital Collections full-text search results, can be reviewed as follows, depending on access restrictions.
(For further details about access restrictions, please refer to About the National Diet Library Digital Collections >3-1. Digitized materials and others
Available without login
Content is accessible via the Internet by anyone. Click Frame Number to jump to the corresponding section.
Available with the Digitized Contents Transmission Service
The Digitized Contents Transmission Service is available to anyone who is an officially registered user of the NDL, resides in Japan, and has agreed to the latest version of the Terms of Service. For details, please refer to the Digitized Contents Transmission Service for Individuals.
Once you have completed the registration process, you can log in to the NDL Digital Collections and browse content as if it were available via the Internet.
The collection can also be browsed from computer terminals at the NDL or at libraries that participate in the Digitized Contents Transmission Service for Libraries. Please refer to the List of Partner Libraries to the Digitized Contents Transmission Service for Libraries.
Available only at the NDL
Books and magazines that are available for browsing only at the NDL will also appear in the results of full-text searches, but you must visit the NDL to browse them.
Remote photoduplication services are available for the content of the NDL Digital Collections. Please consider using this service if you are unable to visit the NDL.
3. Full-text searches of the NDL Lab
The NDL Lab is a website that showcases next-generation library systems that have been developed by the NDL. There are several prototype search services available.
3-1. Full-text searches of the Next Digital Library
The Next Digital Library provides a search function of full text, illustrations, photographs, and diagrams for 80,000 historical materials as well as 280,000 items from books in the public domain via the NDL Digital Collections.
*These texts are acquired via OCR, are not proofread, and might include incorrectly recognized text.
Many classical manuscripts feature characters written in running or variant form, along with variant kana, which can be difficult to decipher without specialized knowledge. Full-text searches for these materials utilize unproofread text acquired via an experimental OCR system developed by the NDL's Research and Development for Next-Generation Systems Office.
As of February 2023, full-text searches for historical materials are not yet available in the NDL Digital Collection. Please use the Next Digital Library to conduct full-text searches of historical materials.
Reference: Experimental conversion of historical materials into text via OCR
3-2. Using full-text data with the NDL Ngram Viewer
The NDL Ngram Viewer allows for analysis and visualization of the occurrence of keywords or phrases along a timeline using full-text data acquired via OCR. Full-text data can be used to compare the occurrence of transliterations of Kenya into Japanese as “ケニア” and “ケニヤ” or to find the first appearance of slang words like ”銀ブラ”, which means taking a stroll in Ginza.
Searches for regular expressions are useful for identifying bulk inconsistencies the spelling of words. The results are also linked to search results in the NDL Digital Collections.
For example, to check spelling inconsistencies of ”ケンブリッジ”, search using ”ケ.ブリ.ジ”, which will provide you with information on candidate search keywords and their frequencies.
For information on NDL Ngram Viewer and regular expressions, please refer to Release of the NDL Ngram Viewer: A Service to Visualize Full-Text Data.
4. Full-text searches of WARP
The Web Archiving Project (WARP) has been archiving websites in Japan and making them available via full-text search. Books, magazines, and dissertations retrieved this way are also contained in the e-books and e-magazines of the NDL Digital Collections, as described in section 2, and full-text searches are available for these publications.
All web pages displayed in search results can be browsed from computer terminals at the NDL, and those for which the rights holders have given permission can also be browsed via the Internet.
For statistics and information on materials subject to collection, please refer to About Web Archiving Project (WARP).
5. Full-text searches of NDL Search
NDL Search offers full-text searches across the NDL Digital Collections and WARP mentioned above.
The results of a full-text search is displayed in the box labeled "Text" shown below the Search result screen.
"Text" result may not be displayed when the search load is high. Please see "検索について(Q＆A)＞連携しているデータベースのすべての資料を検索できますか？ (Japanese only)" for details. Even if you search once and no results are displayed, search results may be displayed when you search again.
For the NDL Digital Collections, when you click on the link to a material of the NDL Digital Collections displayed in the "Text" result from NDL Search, the first page of that material will be displayed. You cannot move to the page containing the search term with one click from NDL Search.
If you would like to view pages containing search terms with one click, please access the NDL Digital Collections and use the full text search function introduced in Section 2 in this page.
For WARP, click on the link to WARP displayed in the search results to view the page.
If you want to use a full-text search within a limited URL range etc., such as "search only within the site of a specific prefecture," please access WARP and use the full-text search function introduced in Section 4 in this page.
6. Web services of other institutions
The following are major web services that provide full-text searches. Please refer to each individual site for information on the scope of coverage and usage.
Repositories that contain doctoral dissertations and bulletins from universities and other institutions may also be available for full-text searches. For more information on how to find doctoral dissertations from Japanese universities, please refer to the list of related articles.