| |||
| key precursor | |||
| precursor material | |||
| forerunner | |||
| chemical precursor; precursor; precursor substance | |||
|
precursor : 46 phrases in 13 subjects |
| Chemistry | 7 |
| Commerce | 1 |
| Earth sciences | 4 |
| Environment | 3 |
| General | 12 |
| Health care | 5 |
| Immigration and citizenship | 1 |
| Industry | 1 |
| Law | 3 |
| Life sciences | 3 |
| Medical | 4 |
| Social science | 1 |
| Transport | 1 |