The USPTO's Patent Public Search database is the most up-to-date patent search source on the Internet. This is the recommended source for starting your patent search. It is updated once a week on Tuesday, as the U.S. government issues patents on this schedule
RIT's Nexis Uni subscription also provides access to TotalPatent One, a database allowing you to cross search patents from five different authorities (US, Europe, UK, Japan, WIPO).