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Chemistry 470

A research guide for Chemistry Thesis Students at Reed College

Creating a Search Strategy

Choosing Keywords

Considering the terms you will use to search is an important step in the search process. Terms that are too broad or narrow can result in overwhelming or incomplete searches. Try keeping a list of keywords or terms that you see others using in articles and databases as you develop your search strategy - your terms will adjust the more you read.

As an example, if you're interested in the behavior of methane gas in landfills, you might explore the following keywords:

  • 174-82-8 (CAS Registry Number)
  • methane (substance name)
  • CH 4 (formula)
  • landfills
  • cover soil
  • soil
  • oxidation
  • oxygen limitation
  • ammonium
  • NH 4 +

Boolean Operators

Remember that when searching indexes for more than one term it is necessary to combine your keywords into one search statement by using Boolean operators, OR and AND (and sometimes NOT).

Operator Use Example
OR Combine similar terms into a group. Will retrieve citations with any of the terms. 174-82-8 or methane or CH 4
AND Combine different terms. Will retrieve citations with all of the terms. methane and soil and landfill
NOT Excludes terms from a search. (Use sparingly.) methane not natural gas

If the search doesn't yield enough results, you might try a broader search without so many restrictions.


Attaching a wild card symbol to the end of a root word is called truncation. When used in a search, the database will search for the root word and alternate endings. For example, oxid* will retrieve items with the words oxidation or oxidize or oxidate. The symbol used for truncation varies from database to database. For example, Scopus uses an asterisk (*). Use the individual database's Help system or your librarian to determine if it allows truncation and what the symbol is.

Databases - SciFinder

Other databases

Scopus - Basic Search

You can search for: documents (includes journal articles, book chapters, conference proceedings), authors, or affiliations.  

Basic Search Tips:

  1. The default search, a document search, includes title, abstract, and author-provided keywords. Scopus connects search terms with an implicit AND when you enter two or more terms.  
  2. Scopus automatically will search for: accented characters, lemmatization (plural / adjectival forms), and equivalents ("behavior" and "behaviour").
  3. Scopus ignores punctuation and stop words ("the", "it", "of").
Table of search operators, use, and examples
Operator Use Example
OR At least one term must appear liver OR cirrhosis
AND Both terms must appear addiction and behavior
AND NOT Exclude one term lung AND NOT cancer
" " Loose phrase search, looks for words together, but will include singular/plurals and wildcards "addictive behavior"
{ } Exact phrase search, looks for the exact phrase or word {color} will return color, not colour
* Wildcard search, looks for the root word and alternate endings or beginnings Enxym* will return enzyme, enzymes, enzymatic, and enzymology
? Wildcard search, looks for the word with any single character in place of the ? ?NA with retrieve RNA or DNA
W/# Proximity search, terms must be # number of words near each other, in any order zika W/2 virus
PRE/# Proximity search, terms must be # number of words near each other, in a order "whole genome" PRE/4 sequence

Limiting Results:

  • Use the left-hand sidebar to search with results.
  • The left-hand search bar also has facets to limit results by: year, author, subject, document type, source, keyword, affiliation, and language.

Scopus - Cited Reference Search

You can use Scopus to conduct a cited reference search. Typically, cited reference searching involves having a scholarly work in-hand that you like and you want to see who else has used that work in their research. 


  1. Search for the work you have in-hand as a document search in Scopus. Include keywords from the title and the last name of the first author.
  2. Locate your work in the search results list.
  3. On the right hand side, you can see how many times the work was cited. 
  4. Click on the Cited by number to open up a search results list of just works that have cited the paper you have in hand.
  5. You can then limit those results or search within them using the facets and search box on the left-hand side.

Scopus Search Results with Cited By column highlighted

PubMed Tips

  1. Automatic Term Mapping: By default, PubMed attemps to match keywords that are entered into the search box are against MeSH headings. If no match is found, the terms are ANDed together and searched in all fields.
  2. Boolean operators in PubMed must be in all caps (AND, OR, NOT)
  3. Logging in to PubMed with your MyNCBI account or your kerberos account allows you to customize the interface in some pretty cool ways:
    • Create a search alert have have PubMed email you new results.
    • Access your search history and rerun searches.
    • Customize your filters to show the ones you might use the most and hide those you don't use.
  4. To find publications from a particular institution, use the Affliation search on the Advanced Search Builder page or search Reed College[Affiliation] from the basic search bar.