Advanced Search
We’ve all gotten spoiled by the simple search interfaces available these days: a single keyword box with no frills. Just plug in some words and Poof! results show up. But most searches, both web search engines and database search interfaces, have advanced searching available as well, and you can save yourself a lot of time by learning to use them. In this post, I’m going to go over a few of the common features available in advanced searches and a few specific examples.
One of the most common advanced search features is also available in most basic searches if you know about it: Boolean logic. The basic Boolean operators available are AND, OR, and NOT. For those unfamiliar with Boolean logic, AND requires that both terms be in the results (chicken AND noodle), OR means that either term can be in the results (girl OR boy), and NOT means that the second term should not show up at all (dog NOT fleas). In many search interfaces you can use Boolean logic by pairing (or tripling, etc.) the terms for each type in parentheses: (dwi AND (teen OR teenager OR adolescent)) NOT madd
I worked up an amusing lesson on Boolean: Three Boolean operators go to a restaurant…
Not all search interfaces allow NOT, but most will do AND and OR. Several web search engines us + for a version of AND and - for NOT, making the above search something like +dwi +(teen OR teenager OR adolescent) -madd
All of this AND, NOT, +, -, etc. gets confusing after a while, which is where the advanced interfaces show up. Google’s advanced search manages this without mathematical logic: All the words=AND, At least one of the words=OR, None of the words=NOT. Yahoo! has similar phrasing: all, any, or none. Most search engines have something similar.
Databases tend to be a little more literal: the advanced search may have several boxes with drop down menus between them with AND, OR, and NOT. My favorite of these is from CSA, which starts with a matrix of three search boxes across and three boxes down.
The horizontal boxes are associated by OR’s and rows are associated by AND as a default, but you can change that to OR or NOT. On top of that, you can add rows, so you can construct very detailed and specific searches if you understand Boolean. (Click on the Advanced Search Tutorial on the CSA page for more details.)
If you have looked carefully at any of the examples so far, you may have noticed that there are more choices. Databases routinely allow you to search by date and publication, and also to specify that a particular keyword be in a particular place, like an author’s name or an article title or abstract. Depending on the complexity of the database, you may have a lot of other choices, like grade level in education databases, or peer-reviewed articles in academic journal databases. Both Google and Yahoo! advanced searches allow you to specify things like domains, file formats, language and dates. Metasearch sites (sites that collect results from more than one search engine) will usually the advanced features available in all the included search engines (see Dogpile’s advanced search).
There are also “command languages” for many search engines and databases. Here’s list of Google’s Advanced Operators, which can be used in any Google search box. I often use site: or inurl: when I’m looking for something on a particular site, but I don’t know what page it’s on. For instance “distance learning” site:worldcatlibraries.org will go to a list of books in OCLC’s web version of WorldCat. Check the help or support pages for more information on special commands in databases and search engines.
In the previous Google example, I used a phrase “distance learning” surrounded by quotes. This is becoming the standard way of indicating that you want a phrase, in other words, a series of words right next to each other in a particular order. “Distance learning” should not return “learning distance” or “learning at a distance”. It could turn up something like “…in the distance. Learning to drive…” since many search interfaces ignore punctuation. (Be careful, though, not all ignore it–it’s very frustrating to realize that you have been searching for ages because of a misplaced comma.)
The final advanced search feature that is fairly common is wildcard searching. A wildcard is a symbol that will match one or more letters or words within a word or phrase. Wildcards are commonly used in databases to search for plurals: cat* could be cat or cats. In some cases, a wildcard can be several letters, so cat* might be cat, cats, or catalog. The particular symbol(s) used and exactly what they can replace differs for each search engine or database, so you’ll have to check the help files for each one. For instance, Google uses an asterisk to represent one or more missing words (cooking * classes could be cooking school classes, or cooking and wine tasting classes). Google doesn’t use a wildcard within words, because they already use “stemming” or the finding of related words (cat will find cat or cats).
For the search engines and databases you use a lot, and any search engine or database that you decide to explore, it’s well worth having a look at the advanced search features. You can save yourself a lot of time paging through results by focusing your search using these features.
