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   843篇
  免费   78篇
各国政治   66篇
工人农民   38篇
世界政治   68篇
外交国际关系   50篇
法律   455篇
中国政治   4篇
政治理论   228篇
综合类   12篇
  2021年   5篇
  2020年   14篇
  2019年   13篇
  2018年   29篇
  2017年   35篇
  2016年   37篇
  2015年   19篇
  2014年   21篇
  2013年   133篇
  2012年   36篇
  2011年   38篇
  2010年   25篇
  2009年   22篇
  2008年   30篇
  2007年   43篇
  2006年   23篇
  2005年   19篇
  2004年   22篇
  2003年   24篇
  2002年   26篇
  2001年   16篇
  2000年   7篇
  1999年   7篇
  1998年   10篇
  1997年   13篇
  1996年   12篇
  1995年   19篇
  1994年   15篇
  1993年   16篇
  1992年   11篇
  1991年   12篇
  1990年   6篇
  1989年   12篇
  1988年   15篇
  1987年   12篇
  1986年   14篇
  1985年   13篇
  1984年   5篇
  1983年   8篇
  1982年   6篇
  1981年   8篇
  1980年   8篇
  1979年   8篇
  1978年   9篇
  1977年   4篇
  1976年   6篇
  1975年   5篇
  1973年   6篇
  1972年   5篇
  1969年   4篇
排序方式: 共有921条查询结果,搜索用时 15 毫秒
841.
842.
An isolated perfused kidney model was used to evaluate the effect of hyperglycemia on renal tubular epithelial cell morphology. Ten Sprague–Dawley rat kidneys were perfused with Krebs–Henseleit buffer containing 70 mmol/L of glucose (five for 1 h and five for 2 h). Two control groups consisted of 10 kidneys perfused with Krebs–Henseleit buffer without hyperglycemia (five for 1 h and five for 2 h), and 10 nonperfused contralateral kidneys placed in the same environment for the same duration. The hyperglycemia group had significantly increased renal tubular vacuolization (p < 0.001) compared to both control groups at 1 and 2 h. The isolated perfused kidney model recapitulates the renal tubular vacuolization phenotype found in hyperglycemia and may be a potential tool for the investigation into causal factors in renal histology. The full pattern of the Armanni–Ebstein phenomenon was not, however, reproduced, suggesting that this change requires more time or involves more complex factors.  相似文献   
843.
Distinguishing between accidental and abusive head trauma in children can be difficult, as there is a lack of baseline data for pediatric cranial fracture patterns. A porcine head model has recently been developed and utilized in a series of studies to investigate the effects of impact energy level, surface type, and constraint condition on cranial fracture patterns. In the current study, an automated pattern recognition method, or a fracture printing interface (FPI), was developed to classify cranial fracture patterns that were associated with different impact scenarios documented in previous experiments. The FPI accurately predicted the energy level when the impact surface type was rigid. Additionally, the FPI was exceedingly successful in determining fractures caused by skulls being dropped with a high‐level energy (97% accuracy). The FPI, currently developed on the porcine data, may in the future be transformed to the task of cranial fracture pattern classification for human infant skulls.  相似文献   
844.
Fatal ketoacidosis due to diabetes mellitus, alcoholism, and starvation may produce characteristic basal vacuolization of renal tubular epithelial cells (RTEC). Septic ketoacidosis has recently been recognized clinically as a distinct condition in which septicemia can lead to elevation of ketones and various anions unrelated to diabetes mellitus, alcoholism, or caloric deprivation. We report four lethal cases with significantly elevated vitreous ketones secondary to sepsis and/or severe localized infection in individuals with no history of diabetes mellitus, alcoholism, or starvation. Three of four cases exhibited typical basal vacuolization of RTEC. We suggest that septic ketoacidosis is an appropriate cause of death in the forensic setting where sepsis or severe localized infection is found with significant ketoacidosis (β‐hydroxybutyrate > 5 mmol/L)—in the absence of diabetes mellitus, alcoholism, starvation, or other states associated with accelerated ketogenesis. The finding of basal vacuolization of RTEC in such cases provides morphological support for the underlying metabolic derangement.  相似文献   
845.
Cases of postmortem canine predation often involve elderly recluses and their dogs. The face, head, and genitalia are targeted. Two unusual cases of postmortem canine predation of abandoned newborns are described to demonstrate an unusual alternative pattern of mutilation related to the small size of the decedents, marked decomposition, and canine scavenging behavior. Both bodies were abandoned/concealed soon after birth and were subsequently disturbed by dogs. Both were markedly decomposed with absent arms. Other injuries included skin and soft tissue defects of the torsos, with loss of distal portions of the right foot and the left lower leg in one case. No interstitial hemorrhage was observed in any of the exposed soft tissue wounds. There were no significant head or neck injuries. These cases show that patterns of postmortem canine predation will vary depending on the age, physical characteristics, degree of decomposition, and location of decedents.  相似文献   
846.
Loeys–Dietz syndrome is a recently described autosomal dominant disorder with underlying vasculopathy characterized by aortic and other vascular aneurysmal dissection/rupture. A 61‐year‐old man is reported who died suddenly and unexpectedly and at autopsy was found to have a ruptured abdominal aortic aneurysm. Additional findings included dolichostenomelia, high‐arched palate, and pectus excavatum. There was a strong family history of Loeys–Dietz syndrome, although the decedent had never been tested. Death was, therefore, due to a ruptured abdominal aortic aneurysm in a case of probable Loeys–Dietz syndrome. Although Loeys–Dietz syndrome shares common characteristics with Marfan and other connective tissue syndromes, it is a distinct entity with a much more aggressive clinical course. Lethal events may not occur until later adult life; however, the identification of the syndrome and differentiation from other connective tissue disorders at autopsy is important so that genetic investigation of close relatives can be undertaken with prophylactic surgical treatment if necessary.  相似文献   
847.
This article outlines a set of criteria for assessing the value of e-consumer protection schemes. It is intended that it be used as a tool, for policy-makers, industry associations, corporations and consumer organisations in all jurisdictions, seeking to assess the appropriateness of their consumer protection regulation. It can be used to devise new, or improve existing, policies, and it can also be used to compare the usefulness of e-consumer protection in different jurisdictions. It commences with a brief review of existing frameworks for the protection of e-consumers, which demonstrates the need for a model that uncompromisingly presents the needs of consumers. An overview of the model is provided, followed by a presentation of the model's key features. A further section identifies the several ways in which the model can be applied in order to improve the usefulness of e-consumer protection. An earlier version of the model was published in checklist form (Clarke R. ‘A Major Impediment to B2C Success is … the Concept 'B2C' Invited Keynote, Proc. ICEC'06, Fredericton NB, Canada, 14–16 August 2006, at http://www.rogerclarke.com/EC/ICEC06.html#TNT). The present article revises and expands that checklist, and presents the rationale underlying each item in it.  相似文献   
848.
From a realist perspective there is a growing body of criminology that can be classified as ‘So What?’ criminology in that it involves a low level of theorisation, thin, inconsistent or vague concepts and categories, embodies a dubious methodology or has little or no policy relevance. The production of ‘So What?’ criminology is, of course, no accident but the outcome of a number of lines of force that have served to shape the nature of mainstream academic criminology in recent years. The aim of this article is to identify some of these lines of force and to assess their impact.  相似文献   
849.
Abstract: Despite having significant internal injuries, victims of motor vehicle accidents may have surprisingly few external manifestations of trauma. The water test describes a technique whereby water placed in an upwardly facing ear results in drainage from the nose and opposite ear, thus demonstrating transcranial passage of water. This sign can be demonstrated in cases of blunt cranial trauma where there is a “hinge” fracture involving the petrous temporal bones bilaterally associated with a ring fracture extending around the foramen magnum posteriorly. Such a fracture results in separation of the posterior and middle cranial fossae providing a track for water to traverse. The water test provides a quick and noninvasive method for demonstrating the presence of a particular type of skull fracture.  相似文献   
850.
Abstract: To determine whether routine decalcification may reduce the amount of stainable iron that is visible on tissue sections, samples of liver and lung tissue with excessive iron stores were placed in three standard decalcifying solutions (i) formic acid [33%], formaldehyde [4%], and NaCl [0.85%]; (ii) formic acid [30%], formaldehyde [4%], and water; and (iii) nitric acid [5%] for 24, 48, 72, and 96 h. After exposure to the decalcifying solutions, the tissues were stained with Perls stain. The slides were examined blind and the intensity of iron staining was scored semiquantitatively from 0 to 3+. The trend in all samples over the course of the experiment (96 h) was for reduction in the intensity of hemosiderin staining. As the amount of stainable hemosiderin in tissues may be significantly altered by decalcification, the absence of hemosiderin in tissues adjacent to a fracture site does not necessarily indicate that the injury was acute.  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