This page covers the following topics:
Stop words are small words that are not indexed. Stop words include such words as a, and, etc., in, of, on and to; the actual list varies depending on how you're searching.
Basically, you don't have to think about stop words at all. The system recognizes stop words and knows how to search as if they weren't there. This method allows the search facility to focus only on the important words in your search expression and allows you to enter any phrase you want without having to remember to leave out any stop words.
The important thing to remember is that if you search using a stop word, the result might contain a different word where the stop word is located. For example, the search reaching the limit would also match "reaching its limit."
A hyphen (-) used between two words is ignored. However, if you are searching for a word or phrase that normally contains a hyphen, you may include it:
Apostrophes should be used when searching contractions. For possessives, the apostrophe may be used in search phrases because the search engine will return results containing the words from the query. A wildcard (*) may be used whenever you are doubtful about word endings.
Ampersands may be used. For best results enclose the search term in quotes:
A period (.) used between two words is ignored by the search engine. However, if you are searching for a word or phrase that normally contains a period, you may include the period, as in cengage.com.
The search engine is not case sensitive. That is, use of capitalization does not affect the results of a search. For example, the following keyword searches are considered the same:
- Plants and animals
- PLANTS and AniMAls
- plaNts AND animALS
Sometimes you might want to find more than just exact matches to a search term. Wildcards let you substitute symbols for one or more letters.
With wildcards, you can match
You can even match words that you're not sure how to spell!
There are three wildcard operators:
|*||An asterisk (*) stands for any number of characters, including none, and is especially useful when you want to find all words that share the same root. For example, pigment* matches pigment, pigments, pigmentation, etc. Note that you must enter at least three (3) non-wildcard characters. So a search on o* is not allowed; rather you need to enter: oba*. An asterisk can also be used within a word, but the other wildcards are more precise for this kind of use.|
|?||A question mark (?) stands for exactly one character and is especially useful when you're uncertain of a spelling. For example, a search like relev?nce means you can match the word relevance even if, like many of us, you can't remember whether it's spelled with ance or ence. A question mark is also useful for finding certain words with variant spellings. For example, defen?e finds both defense (American) and defence (British and Canadian). Multiple question marks in a row stand for the same number of characters as there are question marks. For example, psych????y matches either psychology or psychiatry but not psychotherapy.|
|!||An exclamation point (!) stands for one or no characters and is especially useful when you want to match the singular and plural of a word but not other forms. For example, product! matches product and products but not productive or productivity. The exclamation point can also be used inside a word to match certain variant spellings. For example, colo!r matches both color (American) and colour (British).|
If you see a message about a search being invalid, try adding more letters before the wildcard character.
Logical operators create relationships between search terms, between a term and a result set and between two result sets. They allow you to find the result of the intersection of two search terms or result sets, the combination of two terms or result sets, or the exclusion of a term or result set from a search.
There are three logical operators:
|and||The and operator specifies that both words on either side of the operator must occur in the part of a record you're searching for that record to match. For example, alcohol and pregnancy finds only those records in which both the word alcohol and the word pregnancy occur.|
|or||The or operator specifies that one or the other or both of the words on either side of the operator must occur in the part of a record you're searching for that record to match. For example, dreams or daydreams finds records in which either the word dreams or the word daydreams or both occur.|
|not||The not operator specifies that the word before the operator must occur but the word after the operator must not occur for a record to match. For example, crime not murder finds all records in which the word crime occurs except the ones in which the word murder also occurs.|
Logical operators in a search expression are evaluated in a particular order:
If you want to change the order of evaluation, use the nesting operators.
|Note: Generally speaking, entering two or more search terms without any logical operators between terms is the same as using the N4 proximity operator. So that a search on cats dogs is the same as entering cats N4 dogs. However, certain indexes, like the Document Title index, automatically use the N2 operator between words.|
The search system follows a particular order of evaluation when there are two or more operators in a search expression. First, wildcards are evaluated. Next come proximity operators, which are tightly bound to the words on either side of them. Finally, the logical operators are evaluated: first not and and, followed by or.
You can change the evaluation order of the logical operators by using nesting operators (parentheses). When you nest entries, the search system performs the operation within parentheses first, then merges the result with the part of the entry outside the parentheses.
The search expression race or color and discrimination specifies that you want to find records that contain either the word race or both the words color and discrimination. This expression is equivalent to the expression race or (color and discrimination).
The search expression (race or color) and discrimination specifies that you want to find records that contain either or both of the words race or color and that also contain the word discrimination.
Proximity operators are used between two search terms to indicate that the terms must occur in a record within a specified distance of each other for that record to match. Words that are close to each other are more likely to be related than words that are far apart.
A proximity operator has two components:
There are two proximity operators:
|Wn||The W (within) operator specifies that the word that follows the operator must occur within n words after the word that precedes the operator for a record to match. For example, the search expression shared w3 values matches any records in which the word values occurs three or fewer words after the word shared.|
|Nn||The N (near) operator specifies that the words on either side of the operator must occur within n words of each other in either direction for a record to match. For example, the search expression memory n5 repressed matches any records in which the words memory and repressed occur within five or fewer words of each other in either direction.|
You can use proximity operators only when searching indexes made up of individual words, such as a title index. They are most useful in indexes of large areas of text, such as keyword and full-text indexes.
Note that proximity operators can be used only between two words, not between a word and an expression within nesting operators (parentheses):
Invalid expression: fleas n10 (dogs or cats)
Valid alternative: fleas n10 dogs or fleas n10 cats
You can use range operators to restrict numeric searches (such as publication dates) to a desired range.
|since, after, gt, >||These operators are equivalent and specify that matching articles must have been published more recently than the date that follows the operator. Example: since 28 feb 1999 (published after February 28, 1999).|
|ge||This operator specifies that matching articles must have been published on or after the search date|
|before, lt, <||These operators are equivalent and specify that matching articles must have been published earlier than the date that follows the operator. Example: before 5/8/1998 (published before May 8, 1998).|
|le||This operator specifies that matching articles must have been published on or before the search date|
|to, - (hyphen)||These operators are equivalent and are used between numeric search terms that specify the lower and upper bounds of the search. Example: da jan 10 - jan 17 (published between January 10 and January 17 of the current year).|
|Note: Publication dates are stored as yyyymmdd. Monthlies and bimonthlies have a publication "day" of 00 (e.g., 19990300). For annuals, both the month and day are zero (e.g., 19980000).|
Enclosing your search terms in quotation marks yields results in which the words appear in the specified order adjacent to one another. This may be helpful for keyword and full text (entire document) searches, especially when you are searching for an exact phrase. For example, a search on "Wild Bill" is the same as searching wild W1 bill (using the W proximity operator). That is, the word wild must be followed by the word bill, in that order, with no other words in between.
If the phrase contains the word or or not, and you want those words used literally, not as logical operators, then you must enclose your phrase in quotation marks. For example, if you typed sink or swim, the word or would be treated as a logical operator. However, enclose the phrase in quotation marks as: "sink or swim" and the system will search for those three words together, in the order listed.
A note regarding database collections that contain Subject Guide and/or Publication Searches: these search types ignore quotation marks.
Notice how the system handles these variations, which reflect hypothetical results counts (the examples below apply to Keyword and Entire Document/Full Text searches):
A search on "prescription drugs" yields 5028 results
The system interprets the phrase enclosed in quotation marks as prescription W1 drugs so in this case the system would only find the phrase, prescription drugs and not find the phrase, drugs without a prescription or others like that where the words prescription and drugs are found in any order and/or appear separately.
A search on prescription drugs yields 7134 results
The system interprets this phrase as prescription N4 drugs so that it would find documents with the phrase, prescription drugs, as well as the phrase, drugs without a prescription.
A search on prescription AND drugs yields 10,295 results
In this case, the use of the logical operator AND directs the system to search for documents that contain both words, regardless of order or location within the document (so the search terms may actually appear in two different paragraphs).
See proximity operators and logical operators for more examples.