这个词是什么意思？
A man-made radioactive actinide with atomic symbol Bk, atomic number 97, and atomic weight 247. Its valence can be +3 or +4. Twelve isotopes have been produced with mass numbers 240-251.
中文名称索引；定义为 MeSH 英文原文，尚未逐条译审。MESH:D001603 · MeSH 2026。
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