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   1751篇
  免费   557篇
各国政治   103篇
世界政治   19篇
外交国际关系   81篇
法律   1549篇
中国政治   15篇
政治理论   511篇
综合类   30篇
  2024年   3篇
  2023年   21篇
  2022年   9篇
  2021年   57篇
  2020年   66篇
  2019年   172篇
  2018年   144篇
  2017年   129篇
  2016年   156篇
  2015年   135篇
  2014年   135篇
  2013年   311篇
  2012年   220篇
  2011年   169篇
  2010年   106篇
  2009年   83篇
  2008年   109篇
  2007年   84篇
  2006年   71篇
  2005年   31篇
  2004年   22篇
  2003年   35篇
  2002年   11篇
  2001年   9篇
  2000年   4篇
  1999年   5篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1985年   4篇
  1984年   3篇
  1983年   1篇
排序方式: 共有2308条查询结果,搜索用时 15 毫秒
991.
Current concerns regarding terrorism and international crime highlight the need for new techniques for detecting unknown and hazardous substances. A novel Raman spectroscopy‐based technique, spatially offset Raman spectroscopy (SORS), was recently devised for noninvasively probing the contents of diffusely scattering and opaque containers. Here, we demonstrate a modified portable SORS sensor for detecting concealed substances in‐field under different background lighting conditions. Samples including explosive precursors, drugs, and an organophosphate insecticide (chemical warfare agent surrogate) were concealed inside diffusely scattering packaging including plastic, paper, and cloth. Measurements were carried out under incandescent and fluorescent light as well as under daylight to assess the suitability of the probe for different real‐life conditions. In each case, it was possible to identify the substances against their reference Raman spectra in less than 1 min. The developed sensor has potential for rapid detection of concealed hazardous substances in airports, mail distribution centers, and customs checkpoints.  相似文献   
992.
Four cases of in‐custody or unlawful death are presented as examples of increased bone fragility with an associated increase in fracture rates due to ethanol‐induced osteopenia. In addition, one of the individuals suffered fractures several weeks premortem, allowing some healing to take place. Using radiographs and physical examination, the ribs from these individuals are compared with those retained from three individuals with no history of alcoholism to illustrate diagnostic characteristics that will be notable using standard autopsy and anthropological procedures. Trabecular bone mass is notably decreased in the alcoholic group leading to a greater chance of fracture occurring during conflict, including arrest and in‐custody situations. The average number of perimortem fractures among the alcoholic individuals is 15, while the control group is six. In the case of the individual with healing, the degree of bone repair on the ribs was less than is expected considering the interval between injury and death.  相似文献   
993.
Shoeprints left at the crime scene provide valuable information in criminal investigation due to the distinctive patterns in the sole. Those shoeprints are often incomplete and noisy. In this study, scale‐invariance feature transform is proposed and evaluated for recognition and retrieval of partial and noisy shoeprint images. The proposed method first constructs different scale spaces to detect local extrema in the underlying shoeprint images. Those local extrema are considered as useful key points in the image. Next, the features of those key points are extracted to represent their local patterns around key points. Then, the system computes the cross‐correlation between the query image and each shoeprint image in the database. Experimental results show that full‐size prints and prints from the toe area perform best among all shoeprints. Furthermore, this system also demonstrates its robustness against noise because there is a very slight difference in comparison between original shoeprints and noisy shoeprints.  相似文献   
994.
Variability in ridge density in a sub‐Saharan population sample was studied by counting ridges in three fingerprint areas (two distal regions, radial and ulnar, and one proximal region) on the epidermal surface of the distal phalanx. Study material was obtained from the fingerprint impressions of 100 male sub‐Saharan subjects aged between 18‐ and 48‐years old. The results were compared with those obtained from a Spanish population sample. Sub‐Saharan males presented lower ridge density than Spanish males in the distal regions (radial and ulnar) of all fingers, whereas differences in the proximal region were only observed on some fingers. Using the differences observed between these populations, the likelihood ratio for inferring membership of one of the populations from a fingerprint of unknown origin was calculated; therefore, a ridge density of 14 or less for both areas (ulnar and radial), support an origin sub‐Saharan versus Spanish population.  相似文献   
995.
Multishot firearm suicides are relatively rare and suggest the possibility of homicide. Physical activity following gunshots to the head, the neck, and the thorax does occur, and immediate incapacitation does not occur in every fatal gunshot wound that penetrates the head or perforates the heart. Cancer patients appear to be at increased suicide risk, but alcohol intoxication is less common in such cases. We present—to the best of our knowledge for the first time—a case of a 54‐year old, male, liver cancer sufferer, who under the influence of alcohol, discharged his revolver three times, suffered, among other wounds, a heart‐perforating wound, and died after c. 1.5 h, being able to talk until just before he died. Our case underlines the importance of keeping an open critical mind when dealing with multiple‐gunshot fatalities, especially when posttraumatic physical activity might be crucial in differentiating homicide from suicide.  相似文献   
996.
Accurately estimating the age‐at‐death of adult human skeletons is fundamental in forensic anthropology. This study evaluates the accuracy of two pubic bone age estimation methods—Chen et al. and Suchey‐Brooks. Specimens were obtained from a known collection of modern pubic bones curated at the Maricopa County Forensic Science Center in Phoenix, Arizona. A sample of 296 left male pubic bones of European ancestry was statistically evaluated via bias, absolute mean error, and intra‐ and inter‐observer error. Results indicate that the two methods are similar; the Suchey‐Brooks method is the most accurate for aging young adults (error c. 7 years), while the Revised Chen et al. method is most accurate for aging middle‐age adults (error c. 6 years). Thus, the Chen et al. method is an important contribution to forensic anthropology for aging older adult skeletal remains. There are, however, some limitations such as subjectivity and the intricate scoring system of Chen et al. method.  相似文献   
997.
目的采用免疫组化方法,观察细胞因子信号转导抑制因子-1(SOCS-1)和Bax在冠心病猝死(SCD)者心肌中的表达情况,探讨其对SCD诊断的意义。方法 25例诊断为SCD者心脏样本为实验组,25例非心血管疾病猝死者心脏样本为对照组。应用免疫组织化学方法检测SOCS-1和Bax在心肌中的表达,应用SPSS 17.0软件进行统计处理,组间比较采用秩和检验。结果 SCD猝死者心肌SOCS-1与Bax的表达明显高于对照组,Uc值SOCS-1为5.830 6,Bax为5.573,两种指标组间比较,差异均有显著性意义(P<0.01);SCD组中SOCS-1表达阳性以上且Bax表达弱阳性以上有22例,而正常对照组仅有1例。结论 SOCS-1与Bax均可能参与了细胞凋亡的过程,检测两种指标在心肌中阳性表达,可以为SCD的诊断提供客观依据,且联合检测可提高SCD诊断的特异性。  相似文献   
998.
Book review     
This article looks at the vast contributions political philosopher Hal Pepinsky has made to effecting a peaceful, needs‐meeting vision of justice in the academic fields of criminology and criminal justice over the past three decades. The article examines his life's work as reflected in his most recent book, Peacemaking: Reflections of a Radical Criminologist. This work demonstrates that those who push the boundaries of scholarly disciplines, such as he has done, sometimes find themselves in conflict with those most invested in controlling the allocation of the rewards those disciplines mete out. As Professor Pepinsky increasingly became an outsider he took the risk of taking on the burdens of other outsiders whose pain and suffering the vast majority of his academic colleagues turned their eyes from.  相似文献   
999.
Organizations can survive, let alone progress, only if they carry out meaningful transactions with society at large. This process requires they differentiate their “organizational being” to respond to clientele needs and/or user demands. The inherent problem is that these differentiated structures may become segmented into tightly closed systems, being in effect organizations within organization characterized by self-serving vested interests. Expediency becomes the operating rule. Segmentation is common to all societies, but it is especially prevalent in situations of decline.

Advanced in this discussion is that the segmentation process may be accelerated and consolidated by in-house training and education, and especially by those of a public management character. A plea is made for universities to become more actively engaged in (a) the preparation and placement of “quality” educated persons and (b) the search/development of new public organization.  相似文献   
1000.
Abstract

The article argues that the primary purpose of education, both formal and non‐formal, is the development of interrelated and interdependent sets of human capacity to think, to know and to act by honing social consciousness or awareness, values and skills. Investing in education is therefore viewed as investment in the development of social capital that combines with material resources and other non‐material phenomena to produce goods and services, as well as a favourable spiritual environment for human sustenance and development.

Education in Africa needs a fundamental paradigm change which entails, among other things, focusing on confronting, with a view to correcting and departing from, hegemonic knowledge and knowledge systems that are predicated on racist paradigms that have deliberately and otherwise distorted, and continue to distort, the reality of who Africans really are. The article visits some of the terrains most in need of this change: contestations about the roles Africans and Africa have played in human civilisation during the four main historical periods to date: Africa's leadership as the cradle of humankind or the Naissance of Humanity; Africa's leadership in all fields of knowledge and human achievements at the beginning of modern civilisation up to about the fourteenth century AD; the fifteenth century AD to the present which marks the only period in human development when Africa and Africans have been dominated and marginalised by mainly European civilisation and its global projections; and, the emerging era of the renaissance of Africa and other marginalised peoples.

A model curriculum that requires supplementation by the specific characteristics of each country that adopts it is suggested as a step towards this paradigm change. This modest effort at constructing a model curriculum is informed by the understanding that all Africans and peoples of African descent need to possess some basic, shared common knowledge about Africa, the Diaspora and the world ‐ and to acquire critical approaches to contextualised learning.  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