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原子内电子层结构效应──P区元素不规则性内因探讨
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作者 庄玉贵 《福建师大福清分校学报》 1999年第2期58-62,共5页
本文用整体观点分析了P区元素在第二、四、六周期出现的不规则性。总结了呈现不规则性的规律。建议用“副周期性”来概括。探讨了不规则性呈现规律的内在原因是原子的内电子层结构效应,提出基础化学教学中应给予足够的重视。同时重新... 本文用整体观点分析了P区元素在第二、四、六周期出现的不规则性。总结了呈现不规则性的规律。建议用“副周期性”来概括。探讨了不规则性呈现规律的内在原因是原子的内电子层结构效应,提出基础化学教学中应给予足够的重视。同时重新评价了“惰性电子对效应”。 展开更多
关键词 P区元素 不规则性 副周期性 内电子层 结构效应 惰性电子 原子结构 基础化学教学
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Neuroendocrine liver metastases: Contributions of endoscopy and surgery to primary tumor search 被引量:2
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作者 Herwig Cerwenka 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第10期1009-1014,共6页
Neuroendocrine tumors (NETs) are diagnosed with increasing frequency and patients often present with liver metastases at the time of diagnosis. Apart from treatment of the metastases, resection of the primary tumor at... Neuroendocrine tumors (NETs) are diagnosed with increasing frequency and patients often present with liver metastases at the time of diagnosis. Apart from treatment of the metastases, resection of the primary tumor at an early phase is recommended to prevent complications, although it may be difficult to locate, especially in patients with functionally inactive NETs. Small and multifocal tumors in the jejunum and ileum represent a particular challenge. Primary hepatic neuroendocrine carcinoma is extremely rare and is diagnosed only after exclusion of other primary tumors. Therefore, some uncertainty may remain, as small non-hepatic primary tumors may escape detection. Diagnostic work-up in these patients includes biochemical assays and imaging modalities (also comprising specific techniques of scintigraphy and positron emission tomography). This editorial highlights the contributions of endoscopy and operative exploration to the search for the primary tumor. Besides esophagogastro-duodenoscopy, endoscopic ultrasonography, colonoscopy and bronchoscopy, special endoscopic techniques such as balloon enteroscopy or capsule endoscopy are used with growing experience. Compared with balloon enteroscopy, capsule endoscopy is noninvasive and better tolerated, but it cannot localize a lesion precisely and does not allow biopsy or removal of lesions. Before proceeding to surgery, a discussion of the findings by a tumor board should be a standard procedure. Improvements in diagnostic tools have created new perspectives for the detection of obscure primary tumors in patients with neuroendocrine liver metastases, and these searches are best coordinated by a multidisciplinary team. 展开更多
关键词 Neuroendocrine tumor Neuroendocrine carcinoma Liver metastasis Primary tumor ENDOSCOPY
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