Medical Libraryhttp://laikaspoetnik.wordpress.com/2010/06/08/pubmed-versus-google-scholar-for-retrieving-evidence/
The Precision was 59/467 (13%) in PubMed and 57/80,730 (0.07%) in Google Scholar (p<0.001)!!
Anders ME, & Evans DP (2010). Comparison of PubMed and Google Scholar Literature Searches. Respiratory care, 55 (5), 578-83 PMID: 20420728