SEARCH STRUCTURE
This page provides basic guidelines for database searching. Databases have a variety of requirements, commands,
and defaults. This page is meant as a general overview, not as instruction for any particular database.
Search terms. Selecting the right terms is essential to any successful search. Some databases match terms only
from article titles; others match terms from titles and abstracts, or from the entire record including the journal
title; others use assigned subject headings (also called 'descriptors').
If freetext searching (using 'keywords' that occur in titles, etc.) leads to a useful citation, you can often improve
your results by identifying a descriptor or descriptors for that citation and then doing a new search using the
descriptor or descriptors as search term(s).
Operators. The most common and essential operators are AND and OR. In most databases NOT (or
AND NOT or ANDNOT) is also an operator, but it should be used with caution.
		AND makes your search narrower.
		Example: neuropeptides and anemia
		[Retrieves a citation only if both terms, 'neuropeptides' and 'anemia', occur in the same citation.
		OR makes your search broader.
		Example: plagiodiscus or surirella or cymatopleura
		[Retrieves a record if any one of the three genera is named in the citation. Also retrieves the record if
		any two of the names occur or all three names occur.]
		NOT excludes the term that follows it; that is, it excludes any citation in which the term that follows
		'NOT' occurs.
		Example: scorpion not scorpion fly
		[Excludes records that include the term 'scorpion fly', but otherwise retrieves any record with the
		word 'scorpion'.]
		Example: dams not sacramento
		[Excludes records that refer to dams on the Sacramento River. Would also exclude a citation that
		discussed 'dams on rivers of northern California other than the Sacramento....']
Phrase searching. Most databases allow searching of phrases as well as of single words.
		Example: opossum shrimp
		[Retrieves a record to Neomysis mercedis, the opossum shrimp, but not a record that uses the
		two words separately, as for example 'do coastal opossoms eat tide-pool shrimp?']
		Exception: Instead of treating a phrase as a phrase, some databases use an implicit 'AND'.
		In these databases, opossom shrimp would retrieve 'do coastal opossoms eat tide-pool shrimp?'
Parentheses. Some databases process each search statement from left to right. Others process every
'AND' in the search statement, then every 'OR'. Yet others process 'OR's before 'AND's. In any search
statement that includes both 'AND' and 'OR', use parentheses.
		Example: (blister beetle or meloe franciscanus) and (anthophorid bee or habropoda pallida)
		Example: (somitogenesis and (xenopus laevis or african clawed frog)) or
		(somite and development and videomicroscopy)
Truncation. Most databases use some character such as * or ? or $ or ! as a truncation-symbol that retrieves
any word beginning with the word-fragment that precedes the character.
		Example: phosphoryl*
		[Retrieves phosphorylate, phosphorylated, phosphorylation....]
A truncation-symbol helps expand your search.
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