How to use the Keyword Search

Natural Language Searching

This is similar to the search syntax used by many popular Internet search engines.

A natural language search request is any combination of words, phrases, or sentences. After a natural language search, Keyword Search sorts retrieved documents by their relevance to your search request. Weighting of retrieved documents takes into account: the number of documents each word in your search request appears in (the more documents a word appears in, the less useful it is in distinguishing relevant from irrelevant documents); the number of times each word in the request appears in the documents; and the density of hits in each document. Noise words and search connectors like NOT and OR are ignored.

A plus in front of a word or phrase indicates that the word or phrase must be present, and a minus in front of a word or phrase indicates that the word may not be present. Example:

+"first class mail" +postage -meter

This would find any document that contains "postage" and "first class mail" but not "meter".

Overview of Boolean Search Syntax

NOTE: To use the following boolean syntax you MUST select Search Type="Boolean" in the form above.

A boolean search request consists of a group of words or phrases linked by connectors such as and and or that indicate the relationship between them. Examples:

If you use more than one connector, you should use parentheses to indicate precisely what you want to search for. For example, apple and pear or orange juice could mean (apple and pear) or orange, or it could mean apple and (pear or orange).

Noise words, such as if and the, are ignored in searches.

Search terms may include the following special characters:

Words and Phrases

You do not need to use any special punctuation or commands to search for a phrase. Simply enter the phrase the way it ordinarily appears. You can use a phrase anywhere in a search request. Example:

If a phrase contains a noise word, Keyword Search will skip over the noise word when searching for it. For example, a search for statue of liberty would retrieve any document containing the word statue, any intervening word, and the word liberty.

Punctuation inside of a search word is treated as a space. Thus, can't would be treated as a phrase consisting of two words: can and t. 1843(c)(8)(ii) would become 1843 c 8 ii (four words).

Wildcards (* and ?)

A search word can contain the wildcard characters * and ?. A ? in a word matches any single character, and a * matches any number of characters. The wildcard characters can be in any position in a word. For example:

appl* would match apple, application, etc.

*cipl* would match principle, participle, etc.

appl? would match apply and apple but not apples.

ap*ed would match applied, approved, etc.

Use of the * wildcard character near the beginning of a word will slow searches somewhat.

AND Connector

Use the AND connector in a search request to connect two expressions, both of which must be found in any document retrieved. For example:

apple pie and poached pear would retrieve any document that contained both phrases.

(apple or banana) and (pear w/5 grape) would retrieve any document that (1) contained either apple OR banana, AND (2) contained pear within 5 words of grape.

OR Connector

Use the OR connector in a search request to connect two expressions, at least one of which must be found in any document retrieved. For example, apple pie or poached pear would retrieve any document that contained apple pie, poached pear, or both.

W/N Connector

Use the W/N connector in a search request to specify that one word or phrase must occur within N words of the other. For example, apple w/5 pear would retrieve any document that contained apple within 5 words of pear. The following are examples of search requests using W/N:

Some types of complex expressions using the W/N connector will produce ambiguous results and should not be used. The following are examples of ambiguous search requests:

In general, at least one of the two expressions connected by W/N must be a single word or phrase or a group of words and phrases connected by OR. Example:

Keyword Search uses two built in search words to mark the beginning and end of a file: xfirstword and xlastword. The terms are useful if you want to limit a search to the beginning or end of a file. For example, apple w/10 xlastword would search for apple within 10 words of the end of a document.

NOT and NOT W/N

Use NOT in front of any search expression to reverse its meaning. This allows you to exclude documents from a search. Example:

NOT standing alone can be the start of a search request. For example, not pear would retrieve all documents that did not contain pear.

If NOT is not the first connector in a request, you need to use either AND or OR with NOT:

The NOT W/ ("not within") operator allows you to search for a word or phrase not in association with another word or phrase. Example:

Unlike the W/ operator, NOT W/ is not symmetrical. That is, apple not w/20 pear is not the same as pear not w/20 apple. In the apple not w/20 pear request, Keyword Search searches for apple and excludes cases where apple is too close to pear. In the pear not w/20 apple request, Keyword Search searches for pear and excludes cases where pear is too close to apple.

Numeric Range Searching

A numeric range search is a search for any numbers that fall within a range. To add a numeric range component to a search request, enter the upper and lower bounds of the search separated by ~~ like this:

This request would find any document containing apple within 5 words of a number between 12 and 17.

Numeric range searches only work with positive integers. A numeric range search includes the upper and lower bounds (so 12 and 17 would be retrieved in the above example).

For purposes of numeric range searching, decimal points and commas are treated as spaces and minus signs are ignored. For example, -123,456.78 would be interpreted as: 123 456 78 (three numbers).

Stemming

Stemming extends a search to cover grammatical variations on a word. For example, a search for fish would also find fishing. A search for applied would also find applying, applies, and apply. There are two ways to add stemming to your searches:

1. Check the Stemming box in the search form to enable stemming for all of the words in your search request. Stemming does not slow searches noticeably and is almost always helpful in making sure you find what you want.
2. If you want to add stemming selectively, add a ~ at the end of words that you want stemmed in a search. Example: apply~

Synonym Searching

Synonym searching finds synonyms of a word in a search request. For example, a search for fast would also find quick. You can enable synonym searching for all words in a request or you can enable synonym searching selectively by adding the & character after certain words in a request. Example: fast& w/5 search.

The effect of a synonym search depends on the type of synonym expansion requested on the search form. Keyword Search can expand synonyms using only user-defined synonym sets, using synonyms from Keyword Search's built-in thesaurus, or using synonyms and related words (such as antonyms, related categories, etc.) from Keyword Search's built-in thesaurus.

Fuzzy Searching

Fuzzy searching will find a word even if it is misspelled. For example, a fuzzy search for apple will find appple. Fuzzy searching can be useful when you are searching text that may contain typographical errors, or for text that has been scanned using optical character recognition (OCR). There are two ways to add fuzziness to searches:

1. Enable fuzziness for all of the words in your search request. You can adjust the level of fuzziness from 1 to 10.
2. You can also add fuzziness selectively using the % character. The number of % characters you add determines the number of differences Keyword Search will ignore when searching for a word. The position of the % characters determines how many letters at the start of the word have to match exactly. Examples:

• ba%nana Word must begin with ba and have at most one difference between it and banana.
• b%%anana Word must begin with b and have at most two differences between it and banana.

Phonic Searching

Phonic searching looks for a word that sounds like the word you are searching for and begins with the same letter. For example, a phonic search for Smith will also find Smithe and Smythe.

To ask Keyword Search to search for a word phonically, put a # in front of the word in your search request. Examples: #smith, #johnson

You can also check the Phonic searching box in the search form to enable phonic searching for all words in your search request. Phonic searching is somewhat slower than other types of searching and tends to make searches over-inclusive, so it is usually better to use the # symbol to do phonic searches selectively.

Variable Term Weighting

When Keyword Search sorts search results after a search, by default all words in a request count equally in counting hits. However, you can change this by specifying the relative weights for each term in your search request, like this:

This request would retrieve the same documents as apple and pear but, Keyword Search would weight apple five times as heavily as pear when sorting the results.

In a natural language search, Keyword Search automatically weights terms based on an analysis of their distribution in your documents. If you provide specific term weights in a natural language search, these weights will override the weights Keyword Search would otherwise assign.