Scholarly: These 2 huge databases allow for citation searching, too.
General periodical indexes: (Include scholarly, popular & newspaper resources, in all subjects, but very few sci-tech resources)
Note: These databases -- and others -- can be searched simultaneously via QuickSearch.
Selected Current References:
The National Marine Sanctuaries Media Library is an online vault where a comprehensive collection of select video clips and high-resolution still images from America's underwater treasures are securely stored and available for searchable access and download.
Source for information: ResearchBuzz, February 22, 2009