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Marine Biology: Search Strategies

This guide includes selected print and electronic books, journals, and databases as well as web resources in the field of marine biology.

Get Logical!

Search strategies in most databases are built upon a foundation of Boolean Logic. Depending upon the search platform you may have different options for the construction of a logical search. Boolean Logic at its simplest consists of three basic terms:

  • AND - a term of conjunction - requires both terms to be present. For me to be very happy, I require ice cream AND strawberries
  • OR - a term of disjunction - requires at least one of the terms to be present. For me to be moderately happy, I require ice cream OR strawberries
  • NOT - a term of negation - requires the term to be absent. For me to be tolerable I require dessert NOT cabbage

Remember that searching a database to find articles is essentially a word matching process. The terms you put in your search will be compared to titles, subjects, indexes, abstracts, and sometimes full text of articles to determine if the article will appear in the search results.

Using the Boolean AND

Use AND to add conditions to your search. These terms must all be matched for an article to appear in your results.

When to use AND:

  • You have specific criteria that must be matched for your results to be of any use
  • Your initial search yielded too many results
  • Your initial search yielded too many irrelevant results

e.g. You are researching the impact of invasive lionfish on Caribbean reef ecosystems. Your initial search might look something like:
lionfish AND Caribbean AND reef AND ecology

Things to expect by adding conditions with AND:

  1. The number of results will usually decrease with every condition you add to the search
  2. The relevance of your results should improve because of the criteria you have chosen

Using the Boolean OR

Use OR to add alternative conditions to your search. At least one of the terms must be matched for an article to appear in your results.

When to use OR:

  • You have varied, even unrelated, criteria any one of which would be useful if matched in your results
  • Synonyms exist for a concept you want represented
  • Your initial search yielded too few results
  • You suspect your initial search caused relevant articles to be excluded from your results

e.g. You are researching Red Drum which have various names, both scientific and common. Your search might look something like:

Sciaenops ocellatus OR red drum OR spottail bass OR redfish OR channel bass

Things to expect by adding conditions with OR:

  1. The number of results will usually increase with every alternate condition you add to the search
  2. The relevance of your results may decrease because of the alternate criteria you have chosen

Hot Tip!

Look at the subject categories assigned to an article in the article record. You may discover new terms that can be used as synonyms or alternative search criteria.

Using the Boolean NOT

Use NOT to add exclusions to your search. These terms must not be present for an article to appear in your results.

When to use NOT:

  • You have specific criteria that must not be matched for your results to be of any use
  • Your initial search yielded too many irrelevant results due to the irrelevant context of a required term.

e.g. You are interested in the impact of crude oil upon fish but not the use of cooking oil for frying fish. Your search might look like:

(crude oil AND fish) NOT (cooking OR vegetable OR olive OR palm OR sunflower OR corn)

Things to expect by adding conditions with NOT:

  1. The number of results will often decrease with every negative condition you add to the search
  2. The relevance of your results should improve because of the criteria you have chosen for exclusion

Limiters

Depending upon the database, other search limiters may be available on the search screen, including:

  • Dates - limit your search to articles published within a particular date range
  • Article Type - Primary/Secondary (Article/Review in Web of Science)
  • Peer reviewed or refereed articles - an indicator of a scholarly article

Wildcards

Wild cards are used to add flexibility to your search terms. Available wild cards vary by database so it's worth looking at the help section to determine how they should be used

* The asterisk is used to substitute for zero or more characters within or at the end of a word

e.g. Reproduc* accounts for reproduce, reproduces, reproduced, reproducing, reproduction, and reproductive

? The question mark is used to substitute for a single character (not zero characters)

e.g. Reproduce? accounts for reproduces and reproduced, but not reproduce or reproducing

e.g. Reproduct??? accounts for reproductive and reproduction

$ The dollar sign is used to substitute for zero or one characters. (Web of Science database)

e.g. Colo$r accounts for color and colour (American English and British English)