Classification
UPT - Water pollution control and measurement
76
USN - Waste water treatment
50
UPCE - Water chemistry
42
UPN - Water protection, water quality, clean water
37
UPP - Water pollution
23
UPC - Water - general aspects
14
UPVC - Groundwater
12
UPK - Water resources, water supply
11
UPPE - Biological indicators of water pollution
10
UPTF - Organic pollutants in water
10
UCGE - Control of environmental pollution - analytical methods
9
UPA - Water - handbooks
8
UPVF - Surface waters - streams, rivers, lakes
7
USK - Waste water
7
UCE - Environmental impact, environmental pollution
6
UPW - Drinking water
6
GTA - Hydrology - general
5
LCO - Hydrobiology
5
UA - Environment - general
5
YEC - Law on waters
5
CHRV - Water and its properties
4
UAN - Environment - mathematical methods, computer applications
4
URA - Soil chemistry
4
USNG - Waste water treatment - biological aspects
4
UXAH - Radioisotopes in water
4
LCP - Limnology
3
LWE - Agriculture - general aspects
3
LWH - Agriculture - soil sciences
3
TBWB - Sensors (biological)
3
UCA - Environmental problems, man and environment - general aspects
3
UCGN - Control of environmental pollution - biological methods
3
UMN - Air pollution control and measurement
3
UPTN - Inorganic pollutants in water
3
USG - Waste treatment, waste disposal
3
USNH - Waste water treatment - special methods
3
USR - Slurry, sludge - treatment and use
3
CT - Chemical methods of materials analysis
2
CTYH - Sampling and sample preparation in chemical analysis
2
GMAB - Hydrogeochemistry
2
GTAK - Hydrogeology
2
LAN - Biology - mathematical methods, statistics
2
LCH - Ecology - methods
2
LEL - Botany - lower plants
2
LKHE - Biochemistry - analytical methods
2
LWV - Agriculture - plant protection
2
UCJ - Environmental protection - general aspects
2
UCQ - Environmental technology
2
UCS - Environmental chemistry
2
UEG - Environmental programs and expertises
2
UHC - Area planning and environment
2
more ...