Already available in the Android and iOS apps for Google Drive, Documents, Sheets and Slides - the web version of go Drive will live January 9th to all users.
New ways to search are:
- Narrow your search to a file type from the search box on Android, iOS, and the web.
- Open advanced search instantly from the search box.
- Access recent files or search Drive from the home screen using 3D Touch on iOS.
- Search Drive using the iOS search bar without opening the Drive app.
See the full release notes at http://googleappsupdates.blogspot.com/2015/12/better-search-experience-in-google-drive.html