Russian language 55 mathematics 47 physics 38 physical chemistry 31 nuclear physics 31 organic chemistry 24 mineralogy 18 more ... German language 18 English language 17 chemistry 17 engineering 15 inorganic chemistry 14 Czech language 14 history 13 French language 12 metals 12 functions 11 architecture 10 astronomy 10 Spanish language 10 bibliography 9 general chemistry 9 natural sciences 9 electrotechnics 8 Italian language 8 dictionaries 8 towns 7 polymers 7 science 7 biochemistry 6 less ...