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Logical search operators

You can combine terms into complex queries with Boolean operators. The following operators can be used: AND, +, OR, NOT, and -.

NB! Boolean operators must be typed in CAPITAL LETTERS.


AND, the conjunction operator, is the system’s default operator for multi-term queries that do not include an operator. When using the AND operator, the records included in the search results feature each of the terms in the search fields.

For example, to search for records that include “economics” and “Keynes”:

economics Keynes


economics AND Keynes


The + sign can be used to indicate that the term must appear in each search result.

For example, to search for records that must include “economics” and may include “Keynes”:

+economics Keynes


The OR operator links two terms and finds a matching record if either of the terms exist in a record.

To search for documents that contain either "economics Keynes" or just "Keynes" use the query:

"economics Keynes" OR Keynes


The "!-" operator excludes records that contain the following term.

To search for documents that contain "economics" but not "Keynes" use the query:

economics !-Keynes

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


Note: If the term begins with the operator, it can be included by using the backslash (\). For example: to search for !-merkki hakuehtona (in Finnish) use the query:

\!-merkki hakuehtona

Note: The NOT operator can be used similarly with this operator. However, the NOT operator returns more results, some of which may contain the term following NOT.

Phrase searches

You can search for an exact phrase by putting your search terms in quotation marks.

For example, to search only for records which include the phrase “mediaeval history”, not “mediaeval cultural history” or similar phrases:

"mediaeval history"

You can also use phrase search for single words. Your search will then produce an exact match to your search term without any other conjugations.

Wildcard characters

? replaces one character in your search term.

For example, the terms “text” and “test” can be searched for using the same query:


*replaces no, one or more characters in a search term.

For example, the terms “test”, “tests” and “tester” can be searched for using the query:


You can also use the asterisk in the middle of a search term:


NB! The wildcards ? and * cannot replace the first character in a search term.

Fuzzy searches

A fuzzy search generates results in which words similar to the actual search word also appear.

~ carries out a fuzzy search when used as the last character in a single-term search.

For example, a fuzzy search for the term “roam”:


This search finds such terms as “foam” and “roams”. The similarity of the search to the original term can be regulated with a parameter between zero and one.

The closer the value is to one, the more similar the term will be to the original term. roam~0.8


The default value of the parameter is 0.5 if it is not separately defined for a fuzzy search.

Proximity searches

Proximity searches look for documents in which the search terms are within a specified distance, but not necessarily one after the other.

~ performs a proximity search at the end of a multi-term search when combined with a proximity value.

For example, to search for the terms “economics” and “Keynes” when they appear within a distance of no more than ten terms from each other:

"economics Keynes"~10

Range searches

Range searches can be conducted using either curvy brackets { } or square brackets [ ]. When using curvy brackets, the search takes into account only the values between the terms entered, excluding the terms themselves. Square brackets, in contrast, also include the terms entered in the range searched for.

For example, to search for a term that begins with the letter B or C using the query:

{A TO D}

For example, to search for the values 2002–2003:

[2002 TO 2003]

NB! The word TO between the values must be typed in CAPITAL LETTERS.

Weighted search terms

^ assigns a weight to the search term in a query.

For example, to assign added weight to the search term “Keynes”:

economics Keynes^5