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   10884篇
  免费   373篇
各国政治   592篇
工人农民   488篇
世界政治   715篇
外交国际关系   382篇
法律   6561篇
中国共产党   3篇
中国政治   67篇
政治理论   2354篇
综合类   95篇
  2021年   60篇
  2020年   150篇
  2019年   196篇
  2018年   265篇
  2017年   306篇
  2016年   279篇
  2015年   200篇
  2014年   234篇
  2013年   1284篇
  2012年   301篇
  2011年   323篇
  2010年   246篇
  2009年   285篇
  2008年   322篇
  2007年   306篇
  2006年   336篇
  2005年   313篇
  2004年   304篇
  2003年   285篇
  2002年   292篇
  2001年   308篇
  2000年   309篇
  1999年   230篇
  1998年   156篇
  1997年   158篇
  1996年   140篇
  1995年   129篇
  1994年   127篇
  1993年   132篇
  1992年   205篇
  1991年   215篇
  1990年   202篇
  1989年   194篇
  1988年   187篇
  1987年   196篇
  1986年   185篇
  1985年   181篇
  1984年   172篇
  1983年   179篇
  1982年   103篇
  1981年   100篇
  1980年   86篇
  1979年   111篇
  1978年   82篇
  1977年   78篇
  1976年   68篇
  1975年   62篇
  1974年   67篇
  1973年   77篇
  1972年   65篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Considerable variations in infant mortality rates have occurred within the low-lying region of northern Germany's East Frisia. Individual parishes can be assigned to three specific groups by registered mortality levels for the period 1740–1839. Differences also existed between parishes containing Geest (heathland), bogs, and marshland reflecting specific geographical and environment factors, as well as the structure of the local economy. In both Geest and bog parishes, the level of infant mortality and its trend over time were not homogeneous. In the two marshy river parishes, only environmental factors were significant; both registered the lowest rates of infant mortality. They had fertile soil, extensive grazing land, an exceptionally high number of large agricultural holdings, and households that were above average in size. By contrast, the highest rates of infant mortality were found in one bog and two Geest parishes, but these communities remained heterogeneous in terms of geographical size and population growth and density.  相似文献   
62.
The concentration of thyreoglobulin (tg) was determined for death caused by hanging, strangulation by ligature, and throttling. Cases of sudden death (traumatic aortic rupture, penetrating wounds of the heart) were used for comparison. The mean values in cases of hanging (149.9±202.3 ng/ml), strangulation by ligature (193.1±173.3), manual strangulation (561.6±173.9) are distinguishable from violent acute deaths (23.3±27.6) and living healthy individuals (17.3±16.1). By means of statistical comparisons, significant differences were found between throttling and strangulation by ligature and between throttling and hanging (adjusted P<0.001). In connection with examination of the bodies high tg values can be regarded as a vital reaction in obstructive asphyxia.  相似文献   
63.
64.
Ethanol was determined by gas chromatography in a variety of tissues and body fluids secured at autopsy in 61 cases. The specimens tested included right and left heart blood, femoral blood, pericardial fluid, cerebrospinal fluid, vitreous humor, urine, stomach contents, and brain. Statistical analysis of the cases revealed no significant differences among the various blood sites tested. However, the variations in blood ethanol concentrations among the various sampling sites within each case were as follows: 40 cases showed differences of less than 25%; 16 cases revealed variability between 25% and 50%, 4 cases had differences exceeding 50%. In one case, satisfactory blood analyses could not be accomplished. The larger variances occurred especially in those instances in which stomach alcohol concentration was 0.50% or greater. In one case, the variability amongst the different blood sites exceeded 400% (femoral blood--0.043%, right atrium--0.070%, root of aorta--0.156%); the brain was 0.050%, and the stomach contents was 1.2%. For all 61 cases, variances in blood alcohol content among the different sampling sites in a single cadaver ranged from 1.8 to 428%.  相似文献   
65.
66.
Deoxyribonucleic acid (DNA) typing of ribosomal ribonucleic acid (rRNA) genes was performed with a polymerase chain reaction (PCR) assay for species identification. A variable region of the 28S ribosomal RNA gene was amplified with primers complementary to flanking sequences phylogenetically well conserved. The products of twelve animal DNAs (human, Japanese monkey, dog, cattle, pig, cat, rabbit, mouse, rat, chicken, frog, and fish) were separated by polyacrylamide gel electrophoresis, each revealing a few bands ranging from 150 to 100 base pairs. The band patterns obtained from each DNA sample differed in number and size, which indicates the applicability of the method to species identification. Samples containing either as little as 1 pg of DNA or degraded DNA of 0.2 to 0.5 kb in length were able to give detectable bands. Postmortem human tissue DNAs were tested as an example. They showed a pattern identical to the human control one, which was distinct from those of the other animals examined.  相似文献   
67.
The authors examine the characteristics of threatening and otherwise inappropriate communications sent to members of the U.S. Congress by a sample of 86 subjects, 20 of whom threatened assassination. We quote excerpts from these letters and provide quantitative data on such variables as the volume, duration, form, and appearance of such communications; the enclosures; the subjects' perceived relationships to the recipients; the thematic content of the communications; and the messages and threats communicated. Comparisons between 43 subjects who pursued encounters with members of Congress and 43 who did not revealed 17 factors associated with such pursuit. In this population, threateners were significantly less likely to pursue an encounter than inappropriate letter writers who did not threaten, regardless of the type of threat or the harm threatened. Inappropriate letters to members of Congress are compared with those directed to Hollywood celebrities. Mentally disordered persons writing to public figures often mention and sometimes threaten public figures other than those to whom the letters are addressed, which raises important issues regarding notification of endangered third parties and the sharing of information among protective agencies.  相似文献   
68.
Despite its original purpose to protect and rehabilitate wayward children, the juvenile system has grown more punitive and has embraced the use of harsher punishments, including execution, for juvenile offenders. Relatively little is known, however, about public attitudes toward the use of capital punishment for juveniles. This research explored the determinants of death penalty opinion, identified the minimum age at which respondents were willing to allow a juvenile to be put to death and examined the willingness of respondents to support an alternative sentence of life without the possibility of parole (LWOP). The results suggested that, while one-quarter of the sample was willing to execute juveniles who were fifteen and under at the time of the crime, there was less support for the execution of juveniles than of adults. In addition, of those who supported the use of the death penalty for juveniles, almost one-half would support LWOP as an alternative to the death penalty.  相似文献   
69.
Recent studies point to the potential theoretical and practical benefits of focusing police resources on crime hot spots. However, many scholars have noted that such approaches risk displacing crime or disorder to other places where programs are not in place. Although much attention has been paid to the idea of displacement, methodological problems associated with measuring it have often been overlooked. We try to fill these gaps in measurement and understanding of displacement and the related phenomenon of diffusion of crime control benefits. Our main focus is on immediate spatial displacement or diffusion of crime to areas near the targeted sites of an intervention. Do focused crime prevention efforts at places simply result in a movement of offenders to areas nearby targeted sites—“do they simply move crime around the corner”? Or, conversely, will a crime prevention effort focusing on specific places lead to improvement in areas nearby—what has come to be termed a diffusion of crime control benefits? Our data are drawn from a controlled study of displacement and diffusion in Jersey City, New Jersey. Two sites with substantial street‐level crime and disorder were targeted and carefully monitored during an experimental period. Two neighboring areas were selected as “catchment areas” from which to assess immediate spatial displacement or diffusion. Intensive police interventions were applied to each target site but not to the catchment areas. More than 6,000 20‐minute social observations were conducted in the target and catchment areas. They were supplemented by interviews and ethnographic field observations. Our findings indicate that, at least for crime markets involving drugs and prostitution, crime does not simply move around the corner. Indeed, this study supports the position that the most likely outcome of such focused crime prevention efforts is a diffusion of crime control benefits to nearby areas.  相似文献   
70.
Fragment     
  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