Nature, Science, and PNAS are the three most prestigious general-science journals, and Nature and Science are among the most influential journals overall, based on the journal Impact Factor (IF). In this paper we perform automatic classification of ~50,000 articles in these journals (published in the period 2005-2015) into 14 broad areas, to explore disciplinary profiles and to determine their field-specific IFs. We find that in all three journals the articles from Bioscience, Astronomy, and Geosciences are over-represented, with other areas being under-represented, some of them severely. Discipline-specific IFs in these journals vary greatly, for example, between 18 and 46 for Nature. We find that the areas that have the highest disciplinary IFs are not the ones that contribute the most articles. We also find that publishing articles in these three journals brings prestige for articles in all areas, but at different levels, the least being for Astronomy. Comparing field-specific IFs of Nature, Science and PNAS to other top journals in six largest areas (Bioscience, Medicine, Geosciences, Physics, Astronomy, and Chemistry) these three journals are always among the top seven journals, with Nature being at the very top for all fields except in Medicine.

中文翻译：

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自然、科学和 PNAS——学科概况和影响

Nature、Science 和 PNAS 是三个最负盛名的普通科学期刊，Nature 和 Science 是综合影响因子（IF）的最有影响力的期刊之一。在本文中，我们将这些期刊（发表于 2005-2015 年）中的约 50,000 篇文章自动分类为 14 个广泛领域，以探索学科概况并确定其特定领域的 IF。我们发现，在所有三个期刊中，来自 Bioscience、Astronomy 和 Geosciences 的文章都过多，而其他领域的代表性不足，其中一些严重。这些期刊中特定学科的 IF 差异很大，例如，Nature 的 IF 介于 18 和 46 之间。我们发现，学科 IF 最高的领域并不是贡献文章最多的领域。我们还发现，在这三个期刊上发表文章为所有领域的文章都带来了声望，但在不同的层面上，天文学的影响最小。将 Nature、Science 和 PNAS 的特定领域 IF 与六大领域（生物科学、医学、地球科学、物理学、天文学和化学）的其他顶级期刊进行比较，这三个期刊始终位居前七名，其中自然是最重要的。除医学外的所有领域均名列前茅。