Bibliography search syntax

Terms

A query is broken up into terms and operators. There are two types of terms: Single Terms and Phrases.

A Single Term is a single word such as "monitoring" or "disease".

A Phrase is a group of words surrounded by double quotes such as "electronic monitoring".

Multiple terms can be combined together with Boolean operators to form a more complex query (see below).


 

Fields

The text search supports fielded data. When performing a search you can either specify a field, or use the default field.

You can search any field by typing the field name followed by a colon ":" and then the term you are looking for.

As it happens, the text search index contains one field "title" and the default field. If you want to find the document entitled "ADHERENCE OF ANTIDEPRESSANTS DURING PREGNANCY: MEMS COMPARED WITH THREE OTHER METHODS" which contains the text "Medication Event Monitoring System", you can enter:

title:"MEMS COMPARED" AND "Medication Event Monitoring System"

Note: The field is only valid for the term that it directly precedes, so:

title:MEMS COMPARED

This query will only find "MEMS" in the title field. It will find "COMPARED" in the default field (in this case the "texte" field).


 

Wildcard Searches

The text search supports single and multiple character wildcard searches within single terms (not within phrase queries).

To perform a single character wildcard search use the "?" symbol.

To perform a multiple character wildcard search use the "*" symbol.

The single character wildcard search looks for terms that match that with the single character replaced. For example, to search for "text" or "test" you can use the search:

te?t
Multiple character wildcard searches looks for 0 or more characters. For example, to search for test, tests or tester, you can use the search:

test*
You can also use the wildcard searches in the middle of a term.

te*t
Note: You cannot use a * or ? symbol as the first character of a search.


 

Regular Expression Searches

The text search supports regular expression searches matching a pattern between forward slashes "/". The syntax may change across releases, but the current supported syntax is documented in the RegExp class. For example to find documents containing "hiv" or "hcv":

/h[ic]v/


 

Fuzzy Searches

The text search supports fuzzy searches based on Damerau-Levenshtein Distance. To do a fuzzy search use the tilde, "~", symbol at the end of a Single word Term. For example to search for a term similar in spelling to "schlerosis" use the fuzzy search:

schlerosis~
This search will find terms like schlerosis and sclerosis.

An additional (optional) parameter can specify the maximum number of edits allowed. The value is between 0 and 2, For example:

schlerosis~1
The default that is used if the parameter is not given is 2 edit distances.


 

Proximity Searches

The text search supports finding words are a within a specific distance away. To do a proximity search use the tilde, "~", symbol at the end of a Phrase. For example to search for a "electronic" and "monitoring" within 10 words of each other in a document use the search:

"electronic monitoring"~10


 

Boosting a Term

The text search provides the relevance level of matching documents based on the terms found. To boost a term use the caret, "^", symbol with a boost factor (a number) at the end of the term you are searching. The higher the boost factor, the more relevant the term will be.

Boosting allows you to control the relevance of a document by boosting its term. For example, if you are searching for electronic monitoring, and you want the term "electronic" to be more relevant boost it using the ^ symbol along with the boost factor next to the term. You would type:

electronic^4 monitoring
This will make documents with the term electronic appear more relevant. You can also boost Phrase Terms as in the example:

"electronic monitoring"^4 "MEMS"
By default, the boost factor is 1. Although the boost factor must be positive, it can be less than 1 (e.g. 0.2)


 

Boolean Operators

Boolean operators allow terms to be combined through logic operators. text search supports AND, "+", OR, NOT and "-" as Boolean operators (Note: Boolean operators must be ALL CAPS).

OR

The OR operator is the default conjunction operator. This means that if there is no Boolean operator between two terms, the OR operator is used. The OR operator links two terms and finds a matching document if either of the terms exist in a document. This is equivalent to a union using sets. The symbol || can be used in place of the word OR.

To search for documents that contain either "electronic monitoring" or just "electronic" use the query:

"electronic monitoring" electronic
or

"electronic monitoring" OR electronic

AND

The AND operator matches documents where both terms exist anywhere in the text of a single document. This is equivalent to an intersection using sets. The symbol && can be used in place of the word AND.

To search for documents that contain "electronic monitoring" and "MEMS" use the query:

"electronic monitoring" AND "MEMS"

+

The "+" or required operator requires that the term after the "+" symbol exist somewhere in a the field of a single document.

To search for documents that must contain "electronic" and may contain "monitoring" use the query:

+electronic monitoring

NOT

The NOT operator excludes documents that contain the term after NOT. This is equivalent to a difference using sets. The symbol ! can be used in place of the word NOT.

To search for documents that contain "electronic monitoring" but not "hiv" use the query:

"electronic monitoring" NOT "hiv"
Note: The NOT operator cannot be used with just one term. For example, the following search will return no results:

NOT "electronic monitoring"

-

The "-" or prohibit operator excludes documents that contain the term after the "-" symbol.

To search for documents that contain "electronic monitoring" but not "hiv" use the query:

"electronic monitoring" -"hiv"


 

Grouping

The text search supports using parentheses to group clauses to form sub queries. This can be very useful if you want to control the boolean logic for a query.

To search for either "electronic" or "monitoring" and "hiv" use the query:

(electronic OR monitoring) AND hiv
This eliminates any confusion and makes sure you that hiv must exist and either term electronic or monitoring may exist.


 

Field Grouping

The text search supports using parentheses to group multiple clauses to a single field.

To search for a title that contains both the word "hiv" and the phrase "white coat compliance" use the query:

title:(+hiv +"white coat compliance")


 

Escaping Special Characters

The text search supports escaping special characters that are part of the query syntax. The current list special characters are

 + - && || ! ( ) { } [ ] ^ " ~ * ? : \ /

To escape these character use the \ before the character. For example to search for (1+1):2 use the query:

\(1\+1\)\:2


Loosely based on the Lucene documentation.

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