Site search help

This reference file explains the search syntax for the search engine.

Topics:

• The Basic Search
• Spelling
• Synonyms
• Sorting by Date
• Automatic "and" Queries
• "OR" Searches
• See Your Search Terms in the Results
• Does Capitalisation Matter?
• Does the Search Engine Observe Stop Words?
• Does the Search Engine Use Stemming?
• Refining Your Search
• Excluding Words
• Phrase Searches
• Restricted Searches
• Advanced Operators

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The Basic Search

To enter a query, type in a few descriptive words and press the Go button for a list of relevant results.

The search engine uses sophisticated text-matching techniques to find pages that are both important and relevant to your search. For instance, the search engine analyzes not only the candidate page, but also the pages linking into it to determine the value of the candidate page for your search. The search engine also prefers pages in which your query terms are near each other.

Note: Encrypted, viewable PDF documents are converted to HTML for indexing; however, the HTML is not displayed.

Spelling

A single spelling suggestion is returned with the results for queries where the spell checker has detected a possible spelling mistake.

The spell checker feature is context sensitive. For example, if the query submitted is "sherbourne missal", "sherborne missal" is suggested as an alternative query. However, "michael sherbourne" would not return an alternate query suggestion.

Note: Currently, the spell checker supports only US English.

Synonyms

Synonyms are other words that have the same or similar meanings. They are displayed as "You could also try" on the results page.

Sorting by Date

The Sort by Date feature sorts and presents your search results based on date. The date of each file is returned in the results. Results that do not contain dates are displayed at the end, sorted by relevance.

Automatic "and" Queries

By default, the search engine only returns pages that include all of your search terms. There is no need to include "and" between terms. For example, to search for documents about armenian christianity, enter:

To broaden or restrict the search, include fewer or more terms.

"OR" Searches

The search engine supports the logical "OR" operator. To retrieve pages that include either word A or word B, use an uppercase "OR" between terms. For example, to search for either London or Colindale, enter:

See Your Search Terms in the Results

Every search result lists one or more excerpts from the web page to display how your search terms are used in context on that page. In the excerpt, your search terms are displayed in bold text so that you can quickly determine if that result is from a page you want to visit.

Does Capitalisation Matter?

The search engine searches are not case sensitive. All letters, regardless of how you enter them, are understood as lower case. For example, searches for "lynne brindley,""Lynne Brindley," and"Lynne brindley" all return the same results.

Does the Search Engine Observe Stop Words?

The search engine ignores common words and characters known as stop words. These include most pronouns and articles. The search engine automatically disregards such terms as "where" and "how," as well as certain single digits and single letters. These terms rarely help to narrow a search and can significantly slow searching. If you want to use stop words in your search, use the "+" sign or enclose your phrase containing stop words in quotation marks. Make sure that you include a space before the "+" sign.

For example, to search for Charles I:

You can also include the "+" sign in phrase searches.

Does the Search Engine Use Stemming?

To provide the most accurate results, the search engine does not use "stemming" or support "wildcard" searches. Rather, the search engine searches for exactly the words that you enter into the search box.

For example, searching for "bookbind" or "bookbind*" will not yield "bookbinder" or "bookbinders". If in doubt, try both forms, for example: "bookbinder" and "bookbinders."

Refining Your Search

Since the search engine only returns web pages that contain all of the words in your query, refining or narrowing your search is as simple as adding more words to the search terms you have already entered. The refined query returns a specific subset of the pages that were returned by your original broad query.

Excluding Words

You can exclude a word from your search by putting a minus sign ("-") immediately in front of the term you want to exclude. Make sure you include a space before the minus sign.

For example, the search:

will return pages about bass that do not contain the word "music."

Phrase Searches

You can search for phrases by adding quotation marks. Words enclosed in double quotes ("like this") appear together in all returned documents. Phrase searches using quotation marks are useful when searching for famous sayings or specific names.

Certain characters serve as phrase connectors. Phrase connectors work like quotes because they join your search words in the same way double quotes join your search words. For example, the search:

is treated as a phrase search even though the search words are not enclosed in double quotes. The search engine recognizes hyphens, slashes, periods, equal signs, and apostrophes as phrase connectors.

Restricted Searches

You may also narrow searches by restricting queries in certain ways.

Restrict Type	Query Syntax	Example
to a given location on your site	allinurl; allintitle; inurl; intitle	allinurl:search help see Advanced Operators for details
to specific domains	site:	site:www.bl.uk see Advanced Operators for details
to specific file types like Excel spreadsheets, PDFf docs, etc.	filetype:	filetype:pdf

Directory Restricting

To restrict the directories searched, enter a URL that drills down through the directory structure to the directories or files to be searched. For example, the query [www.bl.uk/treasures/] restricts the search to everything at the manual level. If the trailing slash is not included, as in [www.bl.uk/treasures], then all subdirectories are also searched.

Advanced Operators

The search engine Search supports several advanced operators, which are query words with special functions. A list of the advanced operators with explanation are provided below.

cache:
The search engine keeps the text of the many documents it crawls available in a backed-up format known as "cache." A cached version of a web page can be retrieved if the original page is unavailable (for example, the page's server is down). The cached page appears exactly as it looked when the crawler last crawled it and includes a message (at the top of the page) to indicate that it's a cached version of the page.

The query [cache:] shows the cached version of the web page. For instance, [cache:www.bl.uk] shows the cached page of the Library's website homepage.

Note: There can be no space between cache: and the web page URL in the query.

If you include other words in the query, those words will be highlighted within the cached document. For instance, [cache:www.bl.uk press releases] shows the cached content with the words "press" and "releases" highlighted.

info:
The query [info:] returns all information available for that particular URL. For instance, [info:www.bl.uk] shows information about the Library's website homepage. Note there can be no space between the info: and the web page URL.

site:
If you include [site:] in your query, the results are restricted to those websites in the given domain. For instance, [help site:www.bl.uk] finds pages about help within www.bl.uk. [help site:bl.uk] finds pages about help within bl.uk URLs.

Note: There can be no space between the "site:" and the domain.

link:
The query [link:] enables you to restrict your search to all pages that link to the query page. To do this, use the [link:sampledomain.com] syntax in the search box.

For example, to find all links to British Library's main page, enter:

allintitle:
If you start a query with [allintitle:], the results are restricted to documents with all of the query words in the document's HTML title. For example, [allintitle: library search] only returns documents that have both "library" and "search" in the HTML title.

intitle:
If you include [intitle:] in your query, the search is restricted to results with documents containing that word in the HTML title. For example, [intitle:library search] returns documents that mention the word "library" in their HTML title, and mention the word "search" anywhere in the document either in the title or anywhere else in the document.

Note: There can be no space between the "intitle:" and the following word.

Putting [intitle:] in front of every word in your query is equivalent to putting [allintitle:] at the front of your query. For example, [intitle:library intitle:search] is the same as [allintitle: library search].

allinurl:
If you start a query with [allinurl:], the search is restricted to results with all of the query words in the URL. For example, [allinurl: catalogues newspapers] returns only documents that have both "catalogues" and "newspapers" in the URL.

Note: [allinurl:] works on words, not URL components. In particular, it ignores punctuation. Thus, [allinurl: foo/bar] restricts the results to page with the words "foo" and "bar" in the URL, but doesn't require that they be separated by a slash within that URL, that they be adjacent, or that they be in that particular word order. There is currently no way to enforce these constraints.

inurl:
If you include [inurl:] in your query, the results are restricted to documents containing that word in the URL. For example, [inurl:library search] returns documents that mention the word "library" in their URL and mention the word "search" anywhere in the document either in the URL or anywhere else in the document.

Note: There can be no space between the "inurl:" and the following word.

Note: [inurl:] works on words, not URL components. In particular, it ignores punctuation. Thus, in the query [library inurl:foo/bar], the inurl: operator affects only the word "foo," which is the single word following the inurl: operator, and does not affect the word "bar." The query [library inurl:foo inurl:bar] can be used to require both "foo" and "bar" to be in the URL.

Putting [inurl:] in front of every word in your query is equivalent to putting [allinurl:] at the front of your query. For example, [inurl:catalogues inurl:newspapers] is the same as [allinurl: catalogues newspapers].

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