弦理论最初是为了解释强相互作用力，也就是二次共振模型（1969）。

The theory has its origins in an effort to understand the strong force, the dual resonance model (1969).

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尽管目前有了很多关于核力，核子-核子相互作用甚至是强相互作用的理论，但是各种理论或模型都或多或少地存在一些困难。

At present, though there are many theories about nuclear power and nucleon-nucleon interaction, more difficulties exist in both of these theories or models more or less.

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现在，包括将来一段时期内，人们不得不借助于各种在量子色动力学指导下的夸克模型来研究强相互作用系统。

At present and even in the future, the QCD-inspired model will be a useful tool to explore the secret of strong interaction systems.

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