Google Scholar allows searches for keywords in theses, technical reports, university websites and books.
The free service spans the academic disciplines from medicine and physics to economics and computer science.
Search results are ranked by order of relevance, including the number of citations by other authors, rather than by the number of hits.
While the great majority of recent papers and periodicals are indexed on the web, many have not been easily accessible to the public using normal search engines.
The project involved broad co-operation from academic, scientific and technical publishers to improve indexing of restricted-access material.