Revised Pubmed homepage, advanced search, and limits page.

PubMed Advanced Search, Limits, and Homepage Revised

Changes include:

• Advanced search page was streamlined
• a link to Clipboard was added to the homepage
• a new Limits page with additional limits for dates and search field tags

http://www.nlm.nih.gov/pubs/techbull/jf10/jf10_pm_advanced_search.html