Subject
- Chemical industry1
- Chemistry6
- Chemistry, Organic1
- Chemistry, Physical and theoretical2
- Chemists35
- Chicle industry1
- China1
- Cinchona1
- Colombo Plan1
- Commemorative postage stamps124
- Comoros1
- Congo (Brazzaville)1
- Congresses and conventions7
- Consejo Nacional de Ciencia y Tecnología (Mexico)1
- Convention du mètre (1875)1
- Côte d'Ivoire1
- Cuba2
- Curie, Marie, 1867-19348
- Curie, Pierre, 1859-19063
- Czechoslovakia1