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   1272篇
  免费   82篇
各国政治   112篇
工人农民   62篇
世界政治   187篇
外交国际关系   91篇
法律   674篇
中国政治   9篇
政治理论   219篇
  2023年   18篇
  2022年   13篇
  2021年   29篇
  2020年   50篇
  2019年   54篇
  2018年   78篇
  2017年   72篇
  2016年   64篇
  2015年   43篇
  2014年   67篇
  2013年   215篇
  2012年   54篇
  2011年   45篇
  2010年   33篇
  2009年   26篇
  2008年   39篇
  2007年   43篇
  2006年   46篇
  2005年   38篇
  2004年   39篇
  2003年   37篇
  2002年   23篇
  2001年   26篇
  2000年   39篇
  1999年   12篇
  1998年   8篇
  1997年   9篇
  1996年   4篇
  1995年   7篇
  1994年   10篇
  1993年   8篇
  1992年   9篇
  1991年   8篇
  1990年   5篇
  1989年   4篇
  1988年   7篇
  1987年   8篇
  1986年   5篇
  1985年   3篇
  1983年   2篇
  1982年   4篇
  1980年   4篇
  1979年   6篇
  1978年   6篇
  1977年   2篇
  1973年   8篇
  1972年   2篇
  1971年   7篇
  1965年   5篇
  1963年   2篇
排序方式: 共有1354条查询结果,搜索用时 15 毫秒
81.
Degradation of human DNA extracted from forensic stains is, in most cases, the result of a natural process due to the exposure of the stain samples to the environment. Experiences with degraded DNA from casework samples show that every sample may exhibit different properties in this respect, and that it is difficult to systematically assess the performance of routinely used typing systems for the analysis of degraded DNA samples. Using a batch of artificially degraded DNA with an average fragment size of approx. 200 bp a collaborative exercise was carried out among 38 forensic laboratories from 17 European countries. The results were assessed according to correct allele detection, peak height and balance as well as the occurrence of artefacts. A number of common problems were identified based on these results such as strong peak imbalance in heterozygous genotypes for the larger short tandem repeat (STR) fragments after increased PCR cycle numbers, artefact signals and allelic drop-out. Based on the observations, strategies are discussed to overcome these problems. The strategies include careful balancing of the amount of template DNA and the PCR cycle numbers, the reaction volume and the amount of Taq polymerase. Furthermore, a careful evaluation of the results of the fragment analysis and of automated allele calling is necessary to identify the correct alleles and avoid artefacts.  相似文献   
82.
Allele frequencies for 16 short tandem repeats (STR) loci were determined with a sample of 230-300 unrelated individuals from the population of Rio de Janeiro, Brazil. The loci are the most commonly used in forensic and paternity testing, being analysed by the Identifiler (Applied Biosystems) and PowerPlex 2.1 (Promega) commercial kits. It was proved that Penta E and D18S51 are the most polymorphic loci.  相似文献   
83.
Genotype polymorphism studies at the 13 loci STRs included in the combined DNA index system [CODIS and PCR-based short tandem repeat loci, in: Proceedings of the Second European Symposium on Human Identification, Promega Corporation, Madison, WI, 1998, pp. 73-88; J. Forensic Sci. 46 (2001) 453] (CODIS: D3S1358, HUMvWA31, HUMFGA, D8S1179 D21S11, D18S51, D5S818, D13S317, D7S820, HUMTH01, HUMTPOX, HUMCSF1PO and D16S539) were carried out in a sample of 1429 unrelated Colombian individuals belonging to 25 different departments. As many other countries in Latino-America, Colombia shows an important admixture component, basically integrated by Amerindians, European-descendants and African-descendants. Due to the fact that only partial population analyses have been carried out in the country, the main aim of the present analysis is to establish a database of forensic interest based on the widely used CODIS systems covering the main Colombian regions.  相似文献   
84.
Three hundred and twenty-six to four hundred and fifty-one individuals were typed for 12 STR markers and revealed by silver stain method and assisted by a computer analysis. Forensic and Hardy-Weinberg values were found. The Kodak ds 1D Image Analysis Software V 2.0.3 EDAS DC 120 System was a useful tool for determining the correct size of pattern bands that were out allelic ladders, alleles 18 and 17 from F13A01, 15 from TPOX and 4 from TH01 were determined by this method and some corroborated by automatic analysis.  相似文献   
85.
Allele frequencies for 09 STR autosomal loci (D3S1358, D5S818, D7S820, D8S1179, D13S317, D18S51, D21S11, FGA and VWA) included in the AmpFlSTR Profiler Plus were obtained from a sample of unrelated individuals from Rio Grande do Sul (southern Brazil).  相似文献   
86.
da Veiga FA  Saraiva CB 《危机》2003,24(2):56-67
Relatively few studies have addressed age patterns of suicide using specifically designed and systematized approaches. Our main objective was to identify and characterize age patterns of suicide in Europe, both on cross-sectional and longitudinal perspectives, based on data comprising the two last decades of the 20th century. A second objective was to determine whether some analytical methods could be useful as complementary approaches to the traditional examination of age-specific rate curves. We identified and characterized four patterns: upward-sloping, convex, downward-sloping, and uniform. The first three reproduce patterns previously described, though we propose some modifications to the respective classification criteria. Longitudinally, pattern stability was found for most countries, but some notable exceptions were detected. From the computation of multiple-decrement life tables by European country, period, and gender, we derived cumulative distributions of age at death for suicide. The results indicate that this methodology is a useful tool, not only for describing and summarizing information, but, more importantly, for providing a better understanding of intrinsic features and complexities of the patterns. Finally, we discuss practical implications of the study in the context of previous theories linking age patterns of suicide to sociological and economic dimensions, and we raise a few questions and hypotheses to be addressed in future research.  相似文献   
87.
Diabetes mellitus is a chronic metabolic illness responsible for a great number of deaths. In postmortem diagnosis, because of the difficulty involved in interpreting blood glucose levels and relatively nonspecific pathologic features, biochemical markers in vitreous humor are useful. The aim of this study was to compare the results obtained for the combined determination of lactate and glucose with fructosamine levels recorded in the vitreous humor of two diagnostic groups (one diabetic and the other nondiabetic). The authors intended to ascertain the capacity of different markers measured in vitreous humor to diagnose diabetes mellitus. Fifty-one cadavers (mean age, 58.7 years; standard deviation, 17.09) were studied. The mean postmortem interval was 16.4 hours (standard deviation, 9.05). Cases were assigned to two diagnostic groups according to whether they were previously diagnosed as either diabetic or nondiabetic. Statistically significant differences for glucose, fructosamine, and the sum values of glucose and lactate were found between the two diagnostic groups. The highest levels were obtained in the group of cases with a previous diagnosis of diabetes mellitus. After the comparison of receiver operating characteristic curves, the sum values of glucose and lactate in vitreous humor is a better predictor of antemortem diabetes mellitus than the fructosamine.  相似文献   
88.
The use of the LightCycler for the detection of Y chromosome SNPs   总被引:3,自引:0,他引:3  
A novel methodology based on PCR monitoring on-line with fluorescent formats using the LightCycler for Y chromosome SNP typing is proposed. The main advantages of the system are the time necessary for the analysis (which is around 20 min), the robustness and the accuracy of the method and especially its sensitivity, which permits the detection of the male component in male-female mixtures up to 1:300 for some of the SNPs.Singleplexes of four different SNPs (M9, sY81, SRY-1532 and SRY-2627) as well as two duplexes (M9 and sY81 on the one hand and SRY-1532 and SRY-2627 on the other) were efficiently implemented. A simultaneous amplification and analysis of the four SNPs is also possible. It seems difficult with the current methodology to implement more than a quadruplex.  相似文献   
89.
The authors trace and compare the developments in recorded juvenile delinquency in Hamburg, Prague, Cracow and Budapest from 1991-1997 and then analyse the processing and selection procedures of the various justice systems. They devote special attention to ethnic minorities within this filtering process. The most salient feature is that the crime rates and processing structures in the former socialist countries display considerable similarities. It would almost be possible to speak of a specific type of criminal justice system with a typical form of reaction. While in the West, the large number of suspects is considerably reduced during later stages of selection to a much smaller number (those actually sentenced and/or imprisoned), what the authors call a funnel model, in the East a smaller number of suspected offenders enters this selection process, but tends to remain within it and be sentenced - the cylinder model. These procedural structures have changed little in the 1990s, and there has certainly not been any increasing alignment of the Eastern systems with the Western one. Indeed, the difference has, if anything, become greater. These lower crime statistics as compared with the West - represented here by Hamburg - are, however, not only the result of equally large discrepancies between the real crime rates, but in this regard the pro-active crime prevention measures of the police, which in Hamburg have caused the inclusion of an increased number of juveniles and foreigners in the crime statistics since 1995, have also had a great effect. The research project thus clearly demonstrates the importance of interpreting crime statistics neither as a true representation nor as a distorted reflection of the activities of a criminal justice system. Instead, these statistics should be seen as reflecting specific processing procedures and methods of crime control.  相似文献   
90.
The article presents an analysis of the expected impact of EU accession on the Hungarian education, training and academic research system with a number of recommendations for an integration policy in these sectors. The first part of the article develops four themes: (1) the current level of preparation of the country for accession in the education sector, (2) the possible longer term benefits of accession, (3) the shorter term costs and (4) the most important elements of a policy of integration. A distinction is made between material and cultural, and that of political cost and benefits, the stress being laid on the second. One of the conclusions of the author is that accession may open up a number of new opportunities for the development and modernisation of the country but that these can be exploited only if the country has a coherent sectorial strategy. Specific preparation actions are proposed in the areas of school education, higher education, vocational training and research policy. The article presents a list of the most important short term government measures and the needs for institutional development. It also makes a proposal for possible further themes of investigation and research. This revised version was published online in July 2006 with corrections to the Cover Date.  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