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   16969篇
  免费   1380篇
各国政治   848篇
工人农民   517篇
世界政治   1421篇
外交国际关系   630篇
法律   11099篇
中国共产党   1篇
中国政治   114篇
政治理论   3574篇
综合类   145篇
  2020年   403篇
  2019年   425篇
  2018年   502篇
  2017年   572篇
  2016年   608篇
  2015年   515篇
  2014年   548篇
  2013年   2051篇
  2012年   400篇
  2011年   506篇
  2010年   646篇
  2009年   603篇
  2008年   449篇
  2007年   490篇
  2006年   524篇
  2005年   400篇
  2004年   411篇
  2003年   403篇
  2002年   377篇
  2001年   540篇
  2000年   456篇
  1999年   380篇
  1998年   260篇
  1997年   221篇
  1996年   202篇
  1995年   207篇
  1994年   204篇
  1993年   197篇
  1992年   279篇
  1991年   313篇
  1990年   286篇
  1989年   288篇
  1988年   279篇
  1987年   261篇
  1986年   289篇
  1985年   271篇
  1984年   280篇
  1983年   247篇
  1982年   208篇
  1981年   176篇
  1980年   170篇
  1979年   189篇
  1978年   135篇
  1977年   124篇
  1976年   90篇
  1975年   94篇
  1974年   101篇
  1973年   96篇
  1972年   78篇
  1968年   67篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
A rare and potentially fatal cause of hematemesis is fistula formation between the esophagus and the vascular system. A case report of a 39-year-old woman with congenital aortic arch anomalies hospitalized for treatment of head injuries demonstrates the potential for iatrogenic esophageal trauma to initiate fistula formation between the esophagus and an anomalous arterial system. A literature review revealed 6 other cases of vascular-esophageal fistulae caused by nasogastric esophageal intubation. It is concluded that aortic arch anomalies increase the risk of esophageal injury and subsequent fistula formation from nasogastric esophageal intubation. In addition, the clinical features and pathologic findings of vascular-esophageal fistulae are reviewed.  相似文献   
942.
The diagnosis of sudden infant death syndrome (SIDS) has been an enigma to medical examiners and coroners for decades. The recent drastic decrease in the number of SIDS cases has been associated with infants sleeping supine instead of prone. The apparent relation between sleeping position and SIDS has led to the marketing of several positioning sleep aids. We report a case of the improper use of one such device which resulted in the death of an infant.  相似文献   
943.
A retrospective analysis of 68 cases of fatal childhood pedestrian accidents in South Australia that occurred over a 20-year period from January 1977 to December 1996 was undertaken. The age range was 12 months to 16 years (average, 7.6 years), with a male to female ratio of 41:27. The most common site of significant injury was the head (91.2%), followed by the abdomen (50%), chest (47.1%), and neck (38.2%). The most frequently encountered significant injury combinations involved the head, chest, and abdomen (14.7%); the head and chest (11.8%); and the head, neck, and abdomen (11.8%). Injuries were severe, consisting of extensive compound and comminuted skull fractures, neck fractures, and massive intraparenchymal brain and internal organ damage with avulsions and fragmentation. Non-life-threatening limb injuries occurred in 88% of cases. A distinct subgroup involved infants and younger children playing in driveways at home who were hit by reversing vehicles. The injuries were often of such a severe nature that death was instantaneous and with no possibility of successful medical intervention. More deaths occurred during the winter than summer months.  相似文献   
944.
The present study investigated the effect on witness confidence and accuracy of confusing questions often used by attorneys in court. Participants viewed a videotaped film and were individually questioned about the incident 1 week later. Half the participants were asked questions using six categories of confusing questions (negatives, double negatives, leading, multiple questions, complex syntax, and complex vocabulary); the remaining half were asked for the same information using simply phrased equivalents. Confusing questions reduced participant-witnesses' accuracy and suppressed confidence–accuracy relationships compared with the condition where simplified alternatives were asked. Witness performance was impaired by the fact that mock-witnesses rarely asked for a confusing question to be explained or qualified their answers. This experiment demonstrates the importance of ensuring that lawyers ask witnesses simple, clear, questions.  相似文献   
945.
946.
Forensic psychiatric services in British Columbia   总被引:1,自引:0,他引:1  
  相似文献   
947.
948.
Since the 1970s, a wide body of research has suggested that the accuracy of clinical risk assessments of violence might be increased if clinicians used actuarial tools. Despite considerable progress in recent years in the development of such tools for violence risk assessment, they remain primarily research instruments, largely ignored in daily clinical practice. We argue that because most existing actuarial tools are based on a main effects regression approach, they do not adequately reflect the contingent nature of the clinical assessment processes. To enhance the use of actuarial violence risk assessment tools, we propose a classification tree rather than a main effects regression approach. In addition, we suggest that by employing two decision thresholds for identifying high- and low-risk cases--instead of the standard single threshold--the use of actuarial tools to make dichotomous risk classification decisions may be further enhanced. These claims are supported with empirical data from the MacArthur Violence Risk Assessment Study.  相似文献   
949.
A laboratory study interested in the analysis of human hair for drugs-of-abuse was conducted to determine if drugs could be detected and quantified from hair. Supercritical fluid extraction (SFE) techniques followed by GC-MS analysis were applied to extract amphetamines from hair. The group of amphetamines included methylenedioxyamphetamine (MDA), methylenedioxymetamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA) and internal standard mephentermine (MP). To validate information on amphetamine use in hair, powdered hair samples free from drugs were collected and soaked in a known amphetamine standard solution. Authentic fortified case hair samples taken from known drug users known to have consumed amphetamines were also analyzed for amphetamine. Results from this study show that amphetamine use can be detected in spiked and authentic fortified human hair using SFE techniques for qualitative and quantitative reproducible results.  相似文献   
950.
An unusual form of fatal child abuse is reported in which investigations by the police and the medical examiner were able to distinguish blunt force head trauma followed by postmortem dismemberment from a fatal dog attack. A discussion of the approaches used to ascertain the correct diagnosis is presented, as well as an overview of dog attacks on humans.  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