The trouble is that they are built for people who are relative novices as researchers. Using these mechanisms, researchers largely relinquish control of the search. After the question is posed, the search engine takes over. It retrieves the answer, but often with plenty of irrelevant excess baggage. The sheer quantity of Web engine results can cloud information quality and relevance.
Internet searches look easy.
For those searches which span the Web, choose from several different search engines. Try Infoseek, if you need a search engine which allows a second search limited to searching through the results of the first. Lycos provides a wide variety of proximity connectors. Wield Excite if you feel more comfortable typing questions in plain English. There's more help online.