SweetSearch4Me is designed for elementary students, with results geared to K-5 students. Other resources include tools for school librarians and teachers, biography, and social studies sites. Search results only include 35,000+ websites that research experts, librarians and teachers have approved.
http://4me.sweetsearch.com/
SweetSearch is the K-12 version and it will field additional credible results in the search. If SweetSearch4me results are too limited you may want to use SweetSearch.
http://www.sweetsearch.com/
Kids Click is owned and run by the School of Library and Information Science (SLIS) at Kent State University. KidsClick has no advertising on it.
http://kidsclick.org
Cyber Sleuth Kids is a search engine and guide for the K-12 student. The goal of CyberSleuth-Kids is to provide a safe educational online database of links to help the student sift through the maze of information on the internet. Search by topic of keyword.