The search terms or keywords you use to search are what determine the results you get. Here's a good exercise to help you generate keywords:
1. Express your topic in a topic sentence: "How is pollution in the water supply measured?"
2. Generate keyword search terms by identifying the main ideas or concepts within the topic sentence: "How is pollution in the water supply measured?" --> pollution, water supply, measured
3. Expand your search terms by brainstorming related terms or synonyms that describe your main ideas:
Some databases allow you to enter your search in terms and phrases almost as you would speak to another person, called "natural language" searching. The computer then analyzes the search statement, divides it into search terms, and searches the terms all according to pre-defined rules.
Academic Lexis Nexis is a natural language database, and entering your search can be different than in other databases.
Different concepts can be linked in different ways.
Article databases, online library catalogs, and many popular search engines share several general searching techniques. Once you master these common searching techniques, you will save yourself time and find more relevant results.
You can create complex search strategies by combining keywords using the linking words AND, OR and NOT. For example, if your search terms are economic and development:
Searching the root of a word without specifying a particular ending is one way to find variations on a word that relate to the same core concept without searching each word separately.
Some databases automatically search terms for singular, plural, and various other endings.
Some databases use a truncation symbol to indicate that any ending is acceptable after exactly matching the letters entered.
The actual symbol used will vary among databases. The asterisk (*) is most common, but some use a ? or other symbol, so check your database.
Searching for exact phrases instead of individual words can focus your search so that more results are directly relevant to your topic. Different databases and search engines accomplish this in different ways. Two common ones are:
Remember: Exact phrase searches can focus your results, but they can also miss some relevant results. Searching the phrase "African economic development" may not find "economic development" in Somalia or Nigeria.
In some databases you can restrict searching your terms to specific sections or fields in a database record, for example the article title or author name.
You can tailor your search by combining information from different parts of the record, like combining an author name with a subject term, or focus your search by restricting terms to an article title or abstract.
This is frequently done by using a pull-down menu to select the appropriate field for each search term.