Boolean operators connect your search words. There are three of them.
AND |
 |
Both cat AND dog must appear in the results. |
Narrows the search. |
OR |
 |
Results will contain the words cat OR dog (OR both OR neither). | Broadens the search. |
NOT |
 |
Results will contain cat but NOT dog. | Narrows the search. |
When searching databases, it's extremely important that you connect your synonyms within the search boxes with ORs. Do not use the OR from the pull down on the left; this'll make a huge mess of your search. Only use AND, NOT from the left pull-down. Keeping the ORs within the search boxes will ensure that your boolean operators are executed in the proper order.
Keyword searches are searches that use whatever words you plunk into the search box. Keywords are typically the most important words in your topic.
Most databases and search engines will tear apart words that are input side by side: For example, national ice cream day. Searched as a keyword search--national ice cream day--in JSTOR pulls up 111,127 results. There are a large number of results because national ice cream day, the four words, are being torn apart. They're appearing in your results glued together, but they're also appearing separately. So conceivably, you could have a result by John National whose article contains the words ice, cream and day.
To glue these two words together, you'll need to phrase search. Phrase searches "glue" keywords that normally appear side by side together. To phrase search, put your phrase in between quotes, like so: "national ice cream day".
Searching "national ice cream day" as a phrase, with " " around the words to glue them together in JSTOR pulls in 1 result. This is a significantly smaller number, and a number that will contain far more relevant results.
Phrase searching works with most databases and search engines (Google, Google Scholar), but if it does not--check the help area for more information.
Most databases allow you to narrow your search by selecting specific dates of publication, languages, or publication types. It is best to run your search first, then apply limiters. Some databases will show limits before the search, usually on the advanced search screen: ↓
While others show limits after the search, usually in options in a side column: →
A few allow both options.
These examples are actually both from Academic Search Ultimate.
Specialized subject databases may also have limits unique to the discipline:
Database |
Specialized Search Limits |
|---|---|
| Historical Abstracts and America: History & Life |
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MEDLINE Complete |
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APA PsycInfo |
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ACM Digital Library |
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Databases that contain a mix of full-text and index-only content, often have a checkbox limit for full-text only—like both of the pictured examples above. Don't use it! Even if this database doesn't have the full-text online, some other database may. That's what the 
link is for. That link runs a search for that specific journal in all of the full-text that LVC owns (100,000 journal titles) and will connect you to the full-text of the journal, if it finds it. If it fails, it'll give you the option to get a copy of the material, with the GET IT link.
Wildcards are special characters which stand for ANY letter in the alphabet. The exact symbol used to represent a single variable letter varies from database to database, but common signs are ?, *, #, and $. To find which symbol your database uses--click on Help and search for truncation.
Truncation search |
Will Find |
|---|---|
| psych* | psychology, psychological, psychiatry, psychotic, etc. |
A truncation symbol is a specific type of wildcard used to represent any number of letters (including zero) at the end of a word. An asterisk is the most common truncation symbol, but check the database help if it doesn't work.
Truncators allow you to put the stem of a word in and pull in all results with different "endings", as shown above.
Not all search engines allow wildcards or truncation (the most famous example is Google). And some automatically searching for common variants of each word, particularly plurals.