Classification
YPB - Economy - general aspects
10
AYA - Sciences - general aspects
8
PLA - Astrosciences - general
6
YBB - Law - general
3
YPD - Business economics
3
AHK - Scientific work
2
AHP - Philosophy
2
DAE - Information technology - general
2
EVN - Energy supply - future aspects
2
GRB - Climatology
2
HDS - Neurophysiology, neuroanatomy
2
LAL - Biology - general aspects
2
LEN - Plant physiology
2
LHL - Microbiology - general aspects
2
LTU - Genetic engineering
2
MIAB - Infinitesimal calculus, foundations and textbooks
2
MSU - Economic analysis
2
PKG - Accelerators
2
UPVF - Surface waters - streams, rivers, lakes
2
YPJ - Accounting
2
YPM - National economy
2
YRA - Social studies
2
YRB - Social sciences, sociology
2
AES - Universities, academies - Germany
1
AHF - Research and science
1
AQPT - Bibliographies and databases on special subjects
1
CHTR - Chemistry of mixtures
1
CHVG - Phase equilibria
1
CLP - Colloid chemistry, surface chemistry
1
DGA - Computer types, plants and organization
1
DGE - Personal computers
1
DPA - Electronic data processing - applications
1
EVH - Energy supply - economic growth
1
FAO - Materials science - introductions
1
FCB - Crystal chemistry
1
FDKB - Diffusion in condensed matter
1
FFPE - Thin film electronic properties, semiconductor interfaces
1
FFPG - Multilayer systems, quantum structures
1
FGC - Crystal growth, crystal technology
1
FGK - Thin film technology, epitaxy
1
FHGB - Conventional electron microscopy
1
FHN - Neutron scattering
1
FJP - Optical materials, crystal optics
1
FKGD - Specific magnetic materials
1
FNCD - Dynamics and phase transitions in molecular crystals
1
FNX - Carbon, carbon materials
1
GBA - General geology, historical geology
1
GFAD - Mineral determination
1
GNA - Geology - soil sciences
1
GSA - Applied geodesy
1
more ...