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Literature Search at Roskilde University Library: Search Techniques

In this guide you get an introduction to how and where you can search for literature

Keywords and Building Block Search Strategy

You should always consider your choice of keywords carefully so that they best capture your field of research. Hastily and coincidental keywords will give you equally haphazard search results. You might want to consider including synonyms, abbreviations and conjugations of your keywords. Moreover, try to think of all of the words that might possibly be used to describe your subject. Think of your subject both in more specific terms and in more general terms. Furthermore, as you get further and further in to your field of study you will get a better sense of the terminology, so be prepared to iterate your choices of keywords as you go.

You can organize your keywords in building blocks, where each block serves a particular purpose or describes a facet of your research. In the illustration below the keywords have been sorted into building blocks. From these building blocks you can carry out a so called building block search strategy, where you combine the keywords with Boolean operators. Within the blocks you combine words with OR like this: (diabetes OR diabetic OR "diabetes melllitus"). You can then combine different buildings blocks with AND, meaning that you are searching for resources that has at least one of the words from both building blocks. For instance:

(diabetes OR diabetic OR "diabetes melllitus")


(insulin OR "regular insulin" OR novolin)


(exercise OR sports)


Billede: AU Library

Phrase Searching

By putting citation marks around a multiword concept or a phrase, you direct the database to search for the words in the order they appear, rather than as individual words. Phrase searching can be useful also if you are looking for a specific title.

”Social media”
”work environment”
"climate change" 
"climate crisis"


The wildcard search technique replaces a single letter with a question mark. This gives you a search where any letter could stand in the place of the question mark in your search results. Wildcards are particularly useful with words that are spelled differently in for instance British and American English. Please note that not all databases support wildcards.


Boolean Operators

AND-OR-NOT are so called Boolean operators and they are a way of telling a database how you would like to combine your keywords. You can use Boolean operators to create search strings that you can work with in as well as most other databases.

AND tells the database that you are looking for the intersection of your keywords. That is that you are looking for literature where both your keywords appear. Using AND therefore makes your search narrow.
Example: “Climate crisis” AND “meat consumption”

OR is used when you want to widen your search to include either one or another keyword, for instance in the case of synonyms. OR gives you the union of your keywords.
Example: “climate crisis” OR “Climate Change”
NOT excludes results with selected keywords. It can be useful if for instance like in the example below you are not interested in literature on social media where Facebook is mentioned. Nonetheless, you should use NOT cautiously as you might exclude relevant literature.
Example: ”social media” NOT Facebook
You can combine multiple Boolean operators in a search string. When you do, it is important to use parenthesis to indicate different buildings blocks in your search. 
Example: (”climate crisis” OR “climate change”) AND “meat consumption”

Billede: NWACC Library


By putting an * [asterisk] where you want to truncate the word, your search is widened to find all variations from the stem of the word. Truncation can therefore also be called stemming. Be careful where you place the * – if you place the * too early, you get undesired endings.