首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   810篇
  免费   20篇
各国政治   20篇
工人农民   87篇
世界政治   65篇
外交国际关系   28篇
法律   385篇
中国政治   16篇
政治理论   212篇
综合类   17篇
  2022年   6篇
  2021年   2篇
  2020年   11篇
  2019年   11篇
  2018年   17篇
  2017年   14篇
  2016年   25篇
  2015年   17篇
  2014年   19篇
  2013年   105篇
  2012年   33篇
  2011年   26篇
  2010年   24篇
  2009年   11篇
  2008年   33篇
  2007年   35篇
  2006年   37篇
  2005年   42篇
  2004年   35篇
  2003年   30篇
  2002年   31篇
  2001年   16篇
  2000年   17篇
  1999年   10篇
  1998年   12篇
  1997年   7篇
  1996年   5篇
  1995年   10篇
  1994年   11篇
  1993年   10篇
  1992年   12篇
  1991年   15篇
  1990年   13篇
  1989年   9篇
  1988年   20篇
  1987年   12篇
  1986年   12篇
  1985年   8篇
  1984年   5篇
  1983年   4篇
  1982年   7篇
  1981年   5篇
  1980年   7篇
  1979年   7篇
  1978年   6篇
  1977年   4篇
  1976年   4篇
  1975年   6篇
  1974年   3篇
  1973年   2篇
排序方式: 共有830条查询结果,搜索用时 0 毫秒
681.
When cases of suspected abusive head trauma are adjudicated in courts of law, one of the theories often presented by defense experts is that a normal, healthy infant or child suddenly neurologically deteriorates or dies several weeks to months after birth or minor injury because a preceding subdural hematoma spontaneously rebleeds after a minor traumatic event. This article reviews the underlying scientific basis of subdural hematoma rebleeding as it applies to this courtroom theory.  相似文献   
682.
683.
Operation Condor was a transnational network of organized state-sponsored terrorism that targeted Communist “subversion.” It was operational in the second half of the 1970s. The key member countries were Chile, Argentina, Uruguay, Bolivia, Paraguay, and Brazil (Peru and Equador joined the network later on, with a more marginal role). Based on declassified documents from the United Nations High Commissioner for Refugees in Geneva and on U.S. documents of various origin, this article will assess the development of the Condor network and the U.S. reaction to such manifest acts of state-sponsored terrorism.  相似文献   
684.
685.
When Abusive Head Trauma (AHT) is suspected in a child, a dilated eye examination by an ophthalmologist is an essential part of the medical workup, as the presence and pattern of retinal hemorrhages can have a high positive predictive rate for abusive head injury. This article proposes to review the clinical presentation, pathophysiology, natural history, sequelae, and differential diagnosis of retinal hemorrhages and other ocular lesions associated with AHT.  相似文献   
686.
Abstract

In Stevie Smith's debut novel Novel on Yellow Paper, set in 1936, the narrator Pompey Casmilus recalls several trips to Germany she made in the years shortly before the rise of the Hitler regime. The memories of these German travels are linked to Pompey's love affair with a Swiss-German student named Karl with whom she has spent time in both England and Germany. The essay explores the significance of the German theme in the novel. This theme emerges in Pompey's memories of Germany and Karl, which at first glance appear to be random moments of recollection. However, the German theme also asserts itself in what I call Pompey's German voice, a distinct narrative voice that uses a specific German vocabulary and mimics German speech patterns, which appears at different points throughout the novel and is not exclusively linked to Pompey's memories of Germany. The essay argues that this narrative voice, the Karl-Pompey romance plot and the narrator's obsessive concern with Jewishness combine into an exploration of the Anglo-German relationship in the inter-war years and the attraction which Germany held for some British visitors during the 1920s and early 1930s, an attraction which is linked to previous literary explorations of the country by British writers such as D. H. Lawrence and which by 1936 has taken on an ominous significance as Pompey observes from afar the atrocities being committed within Germany in the name of the Hitler regime.  相似文献   
687.
688.
689.
Indian snakeroot (Rauvolfia serpentina) is a valuable forest product, root extracts of which are used as an antihypertensive drug. Increasing demand led to overharvesting in the wild. Control of international trade is hampered by the inability to identify root samples to the species level. We therefore evaluated the potential of molecular identification by searching for species‐specific DNA polymorphisms. We found two species‐specific indels in the rps16 intron region for R. serpentina. Our DNA barcoding method was tested for its specificity, reproducibility, sensitivity and stability. We included samples of various tissues and ages, which had been treated differently for preservation. DNA extractions were tested in a range of amplification settings and dilutions. Species‐specific rps16 intron sequences were obtained from 79 herbarium accessions and one confiscated root, encompassing 39 different species. Our results demonstrate that molecular analysis provides new perspectives for forensic identification of Indian snakeroot.  相似文献   
690.
Slimming cactus (Hoodia), found only in southwestern Africa, is a well‐known herbal product for losing weight. Consequently, Hoodia extracts are sought‐after worldwide despite a CITES Appendix II status. The failure to eradicate illegal trade is due to problems with detecting and identifying Hoodia using morphological and chemical characters. Our aim was to evaluate the potential of molecular identification of Hoodia based on DNA barcoding. Screening of nrITS1 and psbAtrnH DNA sequences from 26 accessions of Ceropegieae resulted in successful identification, while conventional chemical profiling using DLI‐MS led to inaccurate detection and identification of Hoodia. The presence of Hoodia in herbal products was also successfully established using DNA sequences. A validation procedure of our DNA barcoding protocol demonstrated its robustness to changes in PCR conditions. We conclude that DNA barcoding is an effective tool for Hoodia detection and identification which can contribute to preventing illegal trade.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号