Chemistry: Formulating a Search Strategy

• Identify the main concepts of your research question and use these to carefully select keywords for searching.
• Concepts may be referred to by many different synonymous terms. Use thesauri, encyclopedias, dictionaries, books, and journal articles to find additional terms. Often the first term that comes to mind is not the one used most often in the scientific literature.
• Some databases categorize articles using controlled vocabulary, which is a list of preferred terms for concepts. Controlled vocabulary is organized in a thesaurus. Search the thesaurus to find the preferred terms for the concepts you are interested in. A popular controlled vocabulary used by medical databases such as PubMed and Medline is called the Medical Subject Headings (MeSH). For more information visit the MeSH Tutorial.
• Consider alternate spellings, pluralizations, and short forms.
• Add to your list of keywords as you discover new and better terms while you search.

Chances are your research question contains more than one concept. Use operators to combine these concepts in different ways to narrow or broaden your search. Operators are used differently in different databases (and some databases do not use operators), so check the help section of your database to make sure you are using operators correctly.

• AND: narrow a search by combining concepts. Both keywords must be present for the result to be retrieved.
• OR: broaden a search and/or find alternate spellings and synonyms. One or both keywords must be present for the result to be retrieved.
• NOT: omit a concept. The keyword must not be present for the result to be retrieved.
• “Phrase searching”: find exact phrases.
• Operators can be combined. Use parentheses to control the order in which operators are executed.

If you are getting too many results or you need a specific kind of article, try limiting your search by:

• Publication date
• Document/article type (try limiting to review articles when starting your search)
• Subject area

Sometimes it’s helpful to search for a particular author; for example, you may discover that a particular researcher has done a lot of work on your topic. Author searches can be tricky for several reasons:

• Many authors have common names; it can be hard to narrow the search down to the correct person
• Authors often do not use a consistent name on their publication.
• Life events such as marriage can alter an author’s name.
• Author names that use accents or non-Western scripts may be represented in different ways on different articles.

Here are some tips for author searches:

• Google your author; many have university profiles or personal websites that can provide you with their full name, institutional affiliation, and sometimes even a list of published articles.
• Look your author up in ORCID, a database of researchers that provides each with a unique identifier. This identifier (known as an ORCID iD) can be used in some article databases to uniquely identify your author. Note that many authors do not yet have an ORCID iD.
• Search your author by their full name in Google Scholar. Some authors have Google Scholar Author Profiles with a full list of their publications.
• Look up author searches in the help information for your database.

• Searching can be time consuming so get started early.
• Don’t stop at one search.
• Try different keywords and combine them in different ways.
• Broaden and narrow your searches using operators and limiters.
• Search in several different databases.
• Look at every page of results to make sure a great article isn’t hiding on page 6.
• Try to narrow a results list to less than 100 articles to keep it manageable.
• Use the title and abstract to determine if an article in your results is relevant.
• Err on the side of grabbing too many articles; you can always get rid of articles later.
• Use bibliographic management software to keep track of the articles you find.

If you already have an article that’s relevant to your research question, you can use it to find more relevant articles using citation chaining. Citation chaining has two parts:

1. Look at the list of references at the end of the article to identify earlier works on the topic; and
2. Look up a list of articles that have cited this article to identify later works on the topic. See these guides for instructions on how to find cited references:

• Cited Reference Searching
• Web of Science: What is Cited Reference Search? (video, 2:49)