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Eng 1A, Menendez: California Environmental Issues: Databases

Choosing a database

Find  ArticlesWhen doing research you can speed up the process by choosing the right database for the right task. If you use "search everything" you may find so many results that the best results for your project may be hidden. Go to the A-Z Database List and select one of the following:

Why not use Google for research?

Why use a database rather than Google? A database is more likely to provide you with relevant information of a scholarly nature that is appropriate to college-level research projects. Using Google or another search engine (Bing , Yahoo) will get you results but not high quality results. High quality research includes material written by authorities or writers quoting authorities. 


Databases ...

  • generally contain high-quality information
  • contain peer-reviewed articles
  • contain articles by known authors
  • contain scholarly information
  • are subject-specific
  • support refined searching

The free Web ...

  • offers free access (you get what you pay for!)
  • is not quality controlled
  • is rarely peer-reviewed
  • doesn't always list authors' names
  • contains mostly popular (non-specialized) information
  • has limited search capabilities

Boolean Search Operators

Think of each search word as having a set of results that is connected to it. These sets can be combined in different ways to create larger or smaller sets of results. You can also exclude certain sets from your results. Boolean operators — AND, OR, and NOT — are the tools you use to combine these sets of results.

The table below explains how Boolean operators work.

Boolean Operator Examples Results


Boolean AND


AND combines different terms when both must be present. Use AND to narrow a search.


Boolean OR


OR combines terms when at least one must be present. Use OR to broaden a search.


Boolean NOT


NOT eliminates irrelevant terms from a search. Use NOT when you want to exclude all records that contain a certain term.

Keyword vs. Subject Searching

A keyword search will find a word anywhere in a record: the title, abstract, author, text, etc. (the equivalent of searching "everything" in the library catalog). For example, if you search for fast foods and teenage obesity, you'll retrieve results in which all of these four words appear anywhere in the record at least once. However, you won't find articles that use synonyms of these words, such as overweight or youth.

Subject searching uses subject headings that come from a list of terms that have been assigned to articles based on their subject matter. This means you'll need to know which terms have been assigned for certain subjects. For example, if you want to find articles on fast foods and teenage obesity in Academic Search Premier, you'll need to search for convenience foods and obesity in adolescence. This will retrieve all articles that have been assigned these subject headings, even those that use different wording in the text itself.

Keyword                vs.                 Subject
Natural language words describing your topic. A good way to start your search. Pre-defined "controlled vocabulary" assigned to describe the content of each item in a database or catalog.
More flexible for searching. You can combine terms in any number of ways. Less flexible. You must know the exact controlled vocabulary word or phrase.
Database looks for keywords anywhere in the record (title, author name, subject headings, etc.). Database looks for subjects only in the subject heading or descriptor field, where the most relevant words appear.
Often yields too many or too few results. If a subject heading search yields too many results, you can often select subheadings to narrow the search.
Often yields many irrelevant results. Results are usually very relevant to the topic.