| Acids, Heterocyclic (67 tracked articles) |
| Alkaloids (446 tracked articles) |
| Gemcitabine (2 tracked articles) |
| Heterocyclic Compounds, 1-Ring (721 tracked articles) |
| Heterocyclic Compounds, Bridged-Ring (30 tracked articles) |
| Heterocyclic Compounds, Fused-Ring (831 tracked articles) |
| Heterocyclic Oxides (3 tracked articles) |