الأصناف الرئيسية
2X
الأقسام
الفروع
- 540Chemistry & allied sciences
- 541Physical chemistry
- 542Techniques, equipment & materials
- 543Analytical chemistry
- 544[Unassigned]
- 545[Unassigned]
- 546Inorganic chemistry
- 547Organic chemistry
- 548Crystallography
- 549Mineralogy