... Combining words


Relationships between search terms

If you are going to search with multiple terms at once, you need to specify exactly what the relationship between the search terms is..There are three basic relationships between search terms:

  Both terms must appear in the search result (AND), for example soccer AND Amsterdam
  At least one of the terms must occur (OR), for example soccer OR tennis
  This is also useful for synonyms, e.g. children OR kids
  One term must be excluded (NOT), e.g. reading NOT disorder

Graphically, the relationships between search terms are shown like this:

 

Booleaanse operatoren

 

Sometimes you have to indicate the relationship between search terms yourself by typing AND, OR and NOT between the search terms. In Dutch-language databases you may have to use EN, OF and NIET.

In most databases and search engines you will find a search form in Advanced Search where you can choose one of these options. Often you can also combine the different options.

Example with Web of Science

You are looking for information on the influence of social media on young people. You want to look up publications that contain both terms.

 

Combineren AND

 

Suddenly you realize that adolescents is an important alternative term for teenagers. You adjust your search so that the term social media appears in combination with at least one of the terms teenagers or adolescents.

 

Combineren OR

 

Note: If you combine with both AND and OR then you must place the OR combination within one search field in most advanced search forms (above image). If you don't, the search engine won't know which search terms to combine first and you won't always get the results you want.

Right now, you're not interested in articles about marketing. You want to find articles about social media combined with the terms teenagers or adolescents, but without the terms marketing or advertising.

 

Combineren NOT

 

Your search command results in:

(food OR breakfast OR appetite OR eating OR menu OR vegetables) AND (aged OR elderly OR dementia OR "nursing home") AND ("quality of life" OR social OR well-being OR loneliness OR tasty)

 

Nice to know: Nesting terms


In many databases and some search engines you can also formulate more complex searches: by nesting terms. To indicate what to combine with AND and what to combine with OR and in what order, you can nest terms. You do this using round brackets.


Example:

If you search for

social media AND (teenagers OR adolescents)


you will find documents about teenagers and/or adolescents and social media.

 

If you remove the parentheses

social media AND teenagers OR adolescents


you not only get documents on social media and teenagers, but also documents on adolescents without social media in them.

Combine sets

In come up with search terms, you have seen that each search query consists of more components. For each component, you created a set of appropriate search terms.

The sets consist of word variants, such as translations and synonyms. You connect the terms within a set with OR, because you want to find at least one of these variants. You connect the sets themselves with AND, because you want to find all of them.

In this example, we combine variants of the terms for elderly with variants of the terms for nutrition and its social aspects. This is a schematic representation of this search query:

 

Combineren sets

Je zoekopdracht wordt dus:

Combineren van sets