The Industry 4.0 literature has exponentially grown in the past decade. We aim to understand how this literature has evolved and propose future research opportunities. We focus on four smart dimensions of Industry 4.0: Smart Manufacturing, Smart Products and Services, Smart Supply Chain, and Smart Working. We perform a machine learning-based systematic literature review. Our analysis included 4,973 papers published from 2011 to 2020. We conducted a chronological network analysis considering the growth of these four dimensions and the connections between them. We also analyzed keywords and the main journals publishing on these four smart dimensions. We show that the literature has mainly been devoted to the study of Smart Manufacturing, although attention to the other smart dimensions has been growing in recent years. Smart Working is the less explored dimension, with many opportunities for future research. We show that research opportunities are concentrated in the interfaces between the different smart dimensions. Our findings support the vision of Industry 4.0 as a concept transcending the Smart Manufacturing field, thus creating opportunities for synergies with other related fields. Scholars can use our findings to understand the orientation of journals and gaps that can be fulfilled by future research.

在过去十年中，工业4.0文献呈指数增长。我们旨在了解这些文献如何发展，并提出未来的研究机会。我们专注于工业4.0的四个智能维度：智能制造，智能产品和服务，智能供应链和智能工作。我们执行基于机器学习的系统文献综述。我们的分析包括2011年至2020年发表的4,973篇论文。考虑到这四个方面的增长以及它们之间的联系，我们进行了时间顺序网络分析。我们还分析了这四个方面的关键词和主要期刊。我们显示，尽管近年来对其他智能维度的关注日益增加，但文献主要致力于智能制造的研究。智能工作是一个鲜为人知的领域，它为未来的研究提供了许多机会。我们表明，研究机会集中在不同智能维度之间的接口上。我们的发现支持将工业4.0视为超越智能制造领域的概念的愿景，从而为与其他相关领域的协同创造机会。学者们可以利用我们的发现来理解期刊的方向和将来的研究可以弥补的空白。