Newly discovered antibiotics were often only effective for a narrow spectrum of infections, whereas the first ones had been broadly applicable.

新研发出的抗生素通常只对少数几类感染有用。相比之下，第一代抗生素的适用范围非常广。

These searches also tend to only focus on a narrow spectrum of chemical compounds, but this is where artificial intelligence comes in.

这些探索也往往只关注一个狭窄的化合物谱，但这正是人工智能发挥作用的地方。

It had ruined hundreds, if not thousands, of lives and drastically narrowed the American political spectrum.

它毁掉了数百人， 甚至数千人的生命，并大大缩小了美国的政治范围。