These tools take longer initially but can save time later. They are helpful when making a deep or comprehensive search. However, looking through results can be more time consuming than with only one tool. They also don't usually allow the full features or options that you would have if you used the individual tools. This option allows experienced users to customize their search to receive only the documents they really want.
Boolean engines are very good for complex, or deep searches.
However it is critical that you learn to use Boolean logic first. The following search tools are basically Internet directories for education. These 5 have been chosen because they vary in size tremendously. They also have been popular choices of teachers. Links from these 5 directories are arranged in the eLearners directory to the Internet to give the teacher an organized way to find more quality sites that any one of these directories can provide.