• 662 Videos, Slides, Films

• 164 Ecological regions
• 159 Pollution
• 151 Biotic communities
• 133 Conservation of natural resources
• 128 Environmental protection
• 124 Environmental policy
• 123 Biodiversity
• 117 Environmental law
• 107 Air
• 107 Climatic changes
• 105 Ecology
• 102 Global warming
• 97 Biology
• 96 Natural resources
• 87 Life sciences
• 68 Ecological zones
• 64 Study and teaching
• 59 Water
• 55 Water use
• 49 Toxicology
• 48 Land use
• 45 Water-supply
• 42 Endangered ecosystems
• 42 Endangered species

• 645 Films Media Group
• 570 Infobase
• 93 PBS (Firm)
• 74 Films for the Humanities & Sciences (Firm)
• 42 BBC (Firm)
• 40 Green Planet Films (Firm)
• 30 Film Ideas (Firm)
• 28 BBC Worldwide Learning (Firm)
• 26 Media Policy Center (Firm)
• 17 Alexander Street Press
• 15 CNN (Firm)
• 15 TV Only SAS (Firm)
• 14 Green Interview (Firm)
• 13 Annenberg Learner (Firm)
• 13 Roberts, Paul
• 13 World Wide Entertainment (Firm)
• 12 Australian Broadcasting Corporation (Firm)
• 11 Bloomberg LP
• 11 Van Dorslar, Marianne
• 10 CINEFETE (Firm)
• 10 Camille S. DeBose (Firm)
• 10 MacNeil/Lehrer Productions (Firm)
• 10 National Geographic Digital Media (Firm)
• 9 Filmhub (Firm)
• 8 Cambridge Educational (Firm)

• 654 English
• 5 Unknown
• 2 Spanish
• 1 Indonesian

• 13 Earth (Planet)
• 9 Asia
• 8 United States
• 4 Africa, Sub-Saharan
• 4 North America
• 4 U.S. states
• 3 Africa
• 2 Great Britain
• 2 South Asia
• 1 Antarctica
• 1 Australia
• 1 Central America
• 1 China
• 1 Physical geography
• 1 South America
• 1 Southeast Asia

• 508 Video recordings for the hearing impaired
• 74 Educational films
• 68 Videorecording
• 14 Documentary films
• 6 Video recording
• 3 Instructional television programs
• 2 Nonfiction television programs
• 1 Environmental films

Limit year range