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Chemistry and Chemical Engineering Kemicentrum's library

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Using Boolean operators (AND, OR and NOT) to combine your keywords is a way of making your search smarter and more targeted. Consult the database help screens for additional information and tips.

When you use the operator AND you will narrow your search and get fewer results

When you use the operator OR you will broaden your search and get more results. You often use OR  for synonyms or similar concepts.

When you use the operator NOT you exclude certain words from your search query.

Example:

"household waste" AND (biogas* OR biofuel*) NOT fertilizers

This search query will retrieve documents with the term household waste  and any of the other two words but not the word fertilizers.

The film below is made by Gumberg Library at Duquesne University, Pittsburgh.

This work is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License http://tinyurl.com/yrhz9q

Phrase search

You use phrase search when you want specific words to appear in a specific order. Usually you need to enclose the phrase in double quotes

Example:

"climate change" 

Truncation

Truncation means that you replace the end of a word with a sign, usually the * sign, alllowing you to search everything starting with a certain stemming. Truncation symbols may vary by database, and common symbols include: *, !, ?, or #. Be careful with the truncation symbol. Cell* also  retrieves every article about the instrument cello or the author Cellini. Sometimes it is better to combine word variations with OR instead.

Note! Some databases truncate your words automatically.

Example:

If you write chem* you get chemical, chemistry, etc.

 

Wild cards

žWildcards substitute a symbol for one letter of a word. žThis is useful if a word is spelled in different ways. Wildcard symbols may also vary by database.
ž
žExample:
wom!n = woman, women
 

The film about phrase searching, truncation and wildcards is made by Gumberg Library at Duquesne University, Pittsburgh.

This work is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License http://tinyurl.com/yrhz9q

Databases like Compendex and Web of Science are constructed by entering data in different fields. There are author, title, year and abstract fields (and many more). You can use these fields for limiting your search.

Example:
When searching for Colin Poole you can choose the author field for finding articles by Poole himself, the abstract field for finding articles mentioning him or the title field for finding articles where he is a prominent figure.

Using a thesaurus can be of great help when you want to conduct subject searches. A thesaurus presents words grouped together according to similarity of meaning, for instance containing synonyms and sometimes also antonyms. In a database it can guide you to the controlled vocabulary of subject headings and you will know which synonym to use when searching, and also get suggestions for other search words that are more narrow or more general.

The Thesaurus function helps you by:

 

  • Identifying controlled vocabulary terms
  • Finding synonyms and related terms
  • Improving your search strategy with suggested and narrower terms
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