Classification
EHA - Renewable energy sources
ENA - Energy from biomass and waste
21
EKA - Wind energy
15
EXA - Energy policy
14
EBA - Energy production, energy technology
13
ETC - Energy conversion
10
EVA - Energy demand, energy supply - comprehensive works
9
EVN - Energy supply - future aspects
9
LTN - Biotechnology - biodegradation
8
EVB - Energy supply of Germany
6
UKE - Environment and energy resources
6
EUA - Energy conservation - general
5
EVP - Energy models, energy system analysis
5
EWA - Energy economy
5
LEL - Botany - lower plants
5
LTE - Biotechnology - general aspects
5
TEJ - Electric devices, mechanical devices, magnets, dielectrics
5
UEF - Sustainability
5
UKA - Environmental damage and energy production
5
CNWK - Electric batteries
4
EAA - Energy - reference books
4
ECA - Energy resources
4
EIA - Solar energy - general
4
EMA - Hydroelectric, tidal energy
4
FJB - Electric materials
4
CNW - Electrochemical energy production and conversion
3
CWE - Chemical engineering, chemical industry - general
3
CXX - Hydrogen production - chemistry and technology
3
EAD - Energy - comprehensive works
3
EEA - Coal - general
3
EFA - Petroleum, natural gas
3
ELA - Geothermal energy
3
ESB - Hydrogen energy
3
EYA - Energy problems of developing countries
3
LHL - Microbiology - general aspects
3
LRR - Tissue cultures, cell cultures
3
LTD - Biotechnology - comprehensive works
3
LTT - Enzyme technology, protein engineering
3
LTU - Genetic engineering
3
AFG - Large scale research institutions (Helmholtz Centres)
2
CXRU - Synthetic fuels
2
ESA - Synthetic fuels - utilization
2
LWE - Agriculture - general aspects
2
TED - Electric power - industrial aspect
2
TEDD - Electric power transmission
2
TKJ - Traffic
2
UA - Environment - general
2
UHK - Traffic and environment - incl. automobile exhaust gas
2
UMV - Climatic change
2
YEN - Atomic energy law
2
more ...