Database Help: Advanced Research skills

Some more advanced search operators you may need to use in database searching are listed below.

Wildcards

A wildcard replaces a character or characters in a word and is used to retrieve different spellings (e.g., American vs British word forms).

Common wildcard symbols include ? and #

For example: behavio?r will retrieve behaviour and behavior; organi?ation will retrieve: organisation and organization; p?ediatric, will search paediatric and pediatric.

Wildcard symbols vary from database to database. Check the database help section to identify the correct wildcard and truncation symbols.

Proximity limiters

Proximity limiters, also called adjacency, are used to search for words within a specified number of words from each other.

Using adj3 between two search words would tell the database to find the words in any order and with up to two words between them, i.e., word 2 can be up to three words away from word 1.

For example, cognitive adj3 therapy will find the words cognitive and therapy within two words of each other in either direction. This would retrieve cognitive behavioural therapy, cognitive behavioral therapy (if you use a wildcard), cognitive processing therapy, cognitive group therapy, etc.

Truncation 

Truncation is used to find various word endings and will retrieve variations of a word, such as plurals and nouns, in a database.
The symbol commonly used is the asterisk *.
For example, develop* will retrieve develop, development, developmental, developmentally, developments, etc.

Use truncation carefully.
For example, cat* will retrieve catalogue, catastrophic, catatonic, catfish, catholic …​

You can use a truncation symbol in conjunction with phrase searching. 
For example,  "tandem repeat*" will return the same results for ("tandem repeat" OR "tandem repeats" OR "tandem repeating")

Phrase searching 

Phrase searching instructs the database to search for an exact match on your search words. It is especially useful when individual search words are common.

Most databases require your search terms to be in double quotation marks for phrase searching.

For example, "public health" finds the words as a phrase and in that order.

Tip: turn off smart quotes (curly quotation marks) in your Word document, as the formatting corrupts search strings. For example, "public health" rather than “public health”.

Processing order of priority 

Order of priority :   (  ), OR,  PROXIMITY,  AND   

Searches are processed by brackets first, then from left to right - so place most important terms first.

Nesting

Nesting is a technique that groups search words. When creating a search strategy, consider synonyms for your keywords and group them together as a concept string.

For example ("hand disinfection" OR "hand hygiene" OR handwash*)

Nesting is useful to organise your search concepts into the order you want the database to process them, such as combining synonyms for each search concept. Most database use brackets or parentheses for nesting ( )

Searches are processed by brackets first, then from left to right, and so place the most important terms first.

Databases allow you to limit your search results by, for example, demographic details such as age and sex, and by year of publication.

Care should be taken when using limits, such as language, date, and study design. To prevent bias, it is preferable to include all available studies in the initial search results.

When appraising your results, the criteria from your review protocol can be used to exclude publications that are not relevant to your search.

Check whether any search limits apply:

• Animal / Species / Human
• Age
• Gender
• Year(s) of publication
• Location / Jurisdiction
• Language(s)

These limits should also be included in your search words, or by using search filters on the database search pages.

Other considerations:

• Most cited authors
• Most relevant journals
• Document types

Database records have information listed in certain fields, such as author, title, abstract, keywords, etc. You can direct a database to retrieve articles with your search words in specific fields. This increases the precision of your search and reduces the number of irrelevant results.

To direct the database to find your search words in specific fields, you should apply the appropriate field codes to your search words using the syntax required by that database. Usually, you should use a field code that captures at least 'Title' and 'Abstract.' 

For example:

• To search PubMed for Title and Abstract, add [tiab] to the end of each search term
• To search MEDLINE (Ovid) for Title, Abstract, and Keyword Heading Word, add .ti,kf,ti after each search term

Some platforms (search interfaces) allow you to select search fields within the search builder via a dropdown menu. It is recommended that you refine your search strategy by using a designed search filter, rather than database limits.

Topic: 

Toxicological profiling by hair analysis: Detecting and measuring the abuse of illicit drugs​

Concepts and Synonyms:

Concept 1: "hair analysis"

• Synonyms: "hair analys*"

Concept 2: detect / measure

• Synonyms: concentrat*, detect*, measur*, screen*, test*

Concept 3: "illicit drug"

• Synonyms: "drugs of abuse", "illicit drug*", "illicit substance*", "substance abuse", specific drugs such as fentanyl or oxycodone 

Concept Strings: 

"hair analy*"

(concentrat* OR detect* OR measur* OR screen* OR test*)

("drugs of abuse" OR "illicit drug*" OR "illicit substance" OR "illicit substance*" OR ​"substance abuse")

Search Strategy:  ​

1. ​"hair analy*"
2. AND (concentrat* OR detect* OR measur* OR screen* OR test*)
3. AND ("drugs of abuse" OR "illicit drug*" OR "illicit substance*" OR ​"substance abuse" OR fentanyl OR oxycodone)

​Search String: 

"hair analy*" AND (concentrat* OR detect* OR measur* OR screen* OR test*) AND ("drug* of abuse" OR "illicit drug*" OR "illicit substance*" OR "substance abuse" OR fentanyl OR oxycodone)