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Now we are ready to dive into a more sophisticated search in article databases, aiming to get more relevant studies effectively. Let's first take a look at how to:

Build an effective search statement using Advanced Search
Explore similar articles through citation chaining

Build an Effective Searching Statement

Advanced Search allows you to build a more structured search statement. This helps you find relevant results more efficiently. Many article databases, such as Web of Science or Scopus, offer the Advanced Search function.

With the multiple lines structure, you can type in keywords representing different concepts in separate lines and specify the search field for each line.

Advanced Search
	All Fields Title Subject Journal Title ...	Enter a search term
OR NOT	All Fields Title Subject Journal Title ...	Enter a search term
OR NOT	All Fields Title Subject Journal Title ...	Enter a search term
✚ Add a New Line			Search

You can also apply searching techniques, e.g. combine your search terms with Boolean operators (AND, OR, NOT) to make your search more precise.

Steps to Build a Search Statement in an Article Database

In this example, we will use Web of Science to demonstrate the searching process. Web of Science is a multidisciplinary database covering over 20k peer-reviewed journals. You can apply the techniques to other article databases in your subject area as well.

1. Identify keywords

From the preliminary search, you may have identified a few keywords and related terms for your research topic. Pick 2-4 core keywords that represent different concepts. The keywords are usually nouns or noun phrases.

Assume our research topic is: "The impact of COVID on mental health of University students in Hong Kong".

The keywords picked could be: COVID, mental health, University students, Hong Kong

2. Add keywords & combine them with "AND"

Go to Web of Science database.

Add in more rows to include keywords representing different concents, and use AND to combine the keywords so that the search results will include all these keywords.

To make your search more precise, you may:

Use quotation marks " " to enclose the phrase to search the terms as a phrase. This is known as a phrase search.
Limit your search to specific search field, e.g. Topic (includes Title, Keywords, Abstract), or Title, based on your search results.

In our case:

Advanced Search
	Topic	COVID
AND	Topic	"mental health"
AND	Topic	university students
AND	Topic	Hong Kong
✚ Add Row			Search

When you run this search in Web of Science, you will notice there are very few results. Here we can expand our search by adding alternative keywords.

3. Add synonyms/alternative terms & combine them with "OR"

Use OR to combine the alternative keywords (or synonyms) so that articles containing at least one of the keywords will be included in the results.

You may also:

Use truncations * to include variants of a word, e.g. transmit* searches transmit, transmittion, transmitted, etc.
Use parentheses ( ) to enclose the phrase to specify the order of operators (terms within parentheses will be executed first). This is usually used when you compose the search query in one line with multiple operators.

In our case:

Advanced Search
	Topic	COVID OR coronavirus OR pandemic OR lockdown
AND	Topic	"mental health" OR depression OR anxiety
AND	Topic	university OR college OR "higher education"
AND	Topic	student* OR "young adult*" OR "young people"
AND	Title	"Hong Kong" OR China OR Chinese OR Asia
✚ Add Row			Search

Try this search again and see the difference. Note that we changed the last search field to "Title" so that only articles with the keywords in their title will be retrieved. This again makes our search more specific.

4. Refine search results by applying filters

The last step is to refine your search results using filters, e.g.

Publication year range
Subject category / Research areas
Document type (e.g. articles, review articles, conference papers)
and more

You can find similar filter options in many other article databases.

Don't target for a perfect search statement on your first try! Between the steps 2 and 3, there could be many trial searches involved until you retrieve a manageable number of relevant results. You may discover new keywords or even refine your research topic during the searching process.

Read More Search Tips to learn more about Boolean Operators, Truncation, and Phrase search.

Explore Similar Articles

Once you have identified some key studies, you will probably want to find more similar studies. You can use citation chaining (also referred as Backward and Forward searching) to help you achieve this.

The diagram below illustrates how this works when you are trying to find similar articles of your "perfect" article ("A").

Research is constantly building upon others’ ideas and key findings are linked between papers through citations made by authors.

By tracing the development of your “perfect” article across time, you would be able to find articles ("B") that had an impact on this article and also the articles ("C") it influenced thereafter.

Where to Find Citing Articles?

It is easy to do backward searching - we just need to check the article's reference list. But how do we do forward searching and find the citing articles?

Many article databases offer citation information for the articles covered in the database. These databases are referred as citation databases. You can locate an article's citing articles by tracking terms such as "Cited by", "Times Cited", "Citing articles" or "Citing references".

Here are a few examples from commonly used citation databases:

Example on Web of Science

View this sample article on Web of Science

A - the "perfect" article found on Web of Science
B - find A's references, the articles that had an impact on A
C - find A's citing articles, the articles influenced by A
You can also find some related articles through "You may also like...".
For some articles, you can view the article's references in the context through "Enriched Cited References" feature, i.e. to view references by their location in the paper. References appearing in Results or Discussion may be more relevant to your topic.

Example on Scopus

View this sample article on Scopus

A - the "perfect" article found on Scopus
B - find A's references, the articles that had an impact on A
C - find A's citing articles, the articles influenced by A
You can also find some related articles under "Related documents".

Example on PubMed

View this sample article on PubMed

A - the "perfect" article found on PubMed
B - find A's references, the articles that had an impact on A
C - find A's citing articles, the articles influenced by A
You can also find some related articles under "Similar articles".

Example on Google Scholar

View this sample article on Google Scholar

A - the "perfect" article found on Google Scholar
C - find A's citing articles, the articles influenced by A
You can also find some related articles through "Related articles".

Other citation databases

scite
scite is an AI-powered platform for discovering and evaluating scientific articles via Smart Citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. Search over 1.2 billion citation statements for how methods, arguments, results, claims, and datasets are being used. Visualise how scientific articles cite each other through scite Visualisations. Use scite Reference Check to ensure you cite reliable work by screening against retracted references
IEEE Xplore
provides full text access to literature in electrical and electronic engineering, from IEEE journals, transactions, conference proceedings and also IEEE standards.
Embase
Embase covers over 32 million records from almost 8,300 journals in biomedical literature. Embase platform also allows you to exclude records found in Medline. Embase supports searching in PICO format.
SciFinder-n
It provides access to several Chemical Abstracts Service databases, including Chemical Abstracts, Registry, CASREACT, CHEMLIST, and CHEMCAT. Users may search more than 19 million citations to the chemistry literature by topic, author, CAS Registry Numbers, patent number, and CAS abstract number. More than 22 million chemical substances may be searched by chemical name, chemical structure, CAS Registry Numbers, and formula. Users can also do substructure searching.
CNKI 中國知網
The largest database to cover academic journals in Chinese.

Some free platforms that offer citation info

Semantic Scholar
a free academic search engine that covers 200 million papers sourced from publishers, data providers, and web crawls.
Dimensions
offers free version for discovering scholarly articles, and paid version for datasets, grants, patents, clinical trials and policy documents.
Lens.org
a free platform to discover scholarly works and patents.