history 121 botany 63 physiology 57 architecture 52 agriculture 52 water courses 43 geodesy 36 more ... flóra 26 air force 23 water courses regulation 23 systematic botany 22 military aircrafts 21 hydrology 19 channels 19 railway transport 19 geology 18 water management 18 towns 17 geography 16 osobnosti 16 deposits mining 15 museums 15 industry 15 mathematics 13 measurement 13 ancient monuments 13 radiocommunications 13 inland water traffic 13 military history 13 architectural designs 12 less ...