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   1476篇
  免费   84篇
各国政治   113篇
工人农民   64篇
世界政治   141篇
外交国际关系   118篇
法律   770篇
中国政治   12篇
政治理论   330篇
综合类   12篇
  2024年   3篇
  2023年   20篇
  2022年   23篇
  2021年   26篇
  2020年   47篇
  2019年   65篇
  2018年   65篇
  2017年   73篇
  2016年   78篇
  2015年   51篇
  2014年   67篇
  2013年   225篇
  2012年   72篇
  2011年   48篇
  2010年   43篇
  2009年   50篇
  2008年   59篇
  2007年   70篇
  2006年   48篇
  2005年   56篇
  2004年   42篇
  2003年   39篇
  2002年   46篇
  2001年   23篇
  2000年   20篇
  1999年   24篇
  1998年   14篇
  1997年   9篇
  1996年   9篇
  1995年   15篇
  1994年   9篇
  1993年   4篇
  1992年   20篇
  1991年   7篇
  1990年   6篇
  1989年   10篇
  1988年   8篇
  1987年   6篇
  1986年   7篇
  1985年   6篇
  1984年   3篇
  1983年   7篇
  1982年   4篇
  1981年   2篇
  1980年   4篇
  1975年   4篇
  1974年   2篇
  1973年   2篇
  1969年   4篇
  1966年   5篇
排序方式: 共有1560条查询结果,搜索用时 46 毫秒
871.
在西部大开发的战略性基点上 ,具有核心意义的问题不是区域经济问题而是民族发展问题。西部少数民族问题与农民问题的交织 ,使城乡结构调整与城市化发展成为实现西部大开发战略意义的最基本和最迫切的问题。应突破以往的城市化思路和模式 ,以制度创新作为整个战略选择的基点并把中等城市的发展作为主攻方向 ,才能真正实现西部大开发的战略性意义  相似文献   
872.
A 9-locus microsatellite framework (minimal haplotype), previously developed for forensic purposes so as to facilitate stain analysis, personal identification and kinship testing, has been adopted for the establishment of a large reference database of male European Y-chromosomal haplotypes. The extent of population stratification pertaining to this database, an issue crucial for its practical forensic application, was assessed through analysis of molecular variance (AMOVA) of the 20 regional samples included. Despite the notion of some significant haplotype frequency differences, which were found to correlate with known demographic and historic features of Europeans, AMOVA generally revealed a high level of genetic homogeneity among the populations analyzed. Owing to their high diversity, however, accurate frequency estimation is difficult for Y-STR haplotypes when realistic (i.e. moderately sized) datasets are being used. As expected, strong pair-wise and higher order allelic associations were found to exist between all markers studied, implying that haplotype frequencies cannot be estimated as products of allele frequencies. A new extrapolation method was therefore developed which treats haplotype frequencies as random variables and generates estimates of the underlying distribution functions on the basis of closely related haplotypes. This approach, termed frequency 'surveying', is based upon standard population genetics theory and can in principle be applied to any combination of markers located on the Y-chromosome or in the mitochondrial genome. Application of the method to the quality assured reference Y-STR haplotype database described herein will prove very useful for the evaluation of positive trace-donor matches in forensic casework.  相似文献   
873.
An analysis is given of Kantorovich's method of resolving multipliers. It is shown that the method is equivalent to a parametric method but that it is also equivalent with the simplex method with a special rule for the choice of the new basic variable.  相似文献   
874.
Child neglect, the failure to adequately meet a youngster's care needs, is the most frequent form of child maltreatment reported to welfare authorities. However, there have been few empirical reports of treatment outcomes for adjudicated, child neglectful parents. In the current study, an initial assessment of three neglectful parents revealed substantial deficits in cognitive problem-solving skills related to child care judgment. Treatment, consisting of modeling, shaping, practice, and feedback was used to improve each parent's child care problem-solving skills in a multiple baseline design. Skill enhancement was also found for untrained (generalization) problem situations, and independent caseworker ratings of each family's functioning provided external validation of the intervention's clinical impact.  相似文献   
875.
A substantial minority (35%) of the Dutch population is in favor of capital punishment. In this paper, it is argued that in a staunchly abolitionist country such as The Netherlands, the existence and perseverance of such support can be better understood and explained by conceiving of capital punishment support in attitudinal terms as part of a law and order syndrome. Death penalty attitudes are analyzed by means of hierarchic logistic regression analysis. It is shown that support can be modeled quite well, partly in terms of general attitudes to criminal justice, partly in terms of political and sociodemographic parameters. Within the criminal justice attitudes complex, more support is found among those endorsing harsh treatment of offenders, those willing to grant far-reaching powers to justice authorities, those believing that the government is not delivering on the topic of crime fighting, and those who are concerned about the level of crime. Within the political context, more support is enlisted among people who abstain from voting and those who vote at either extreme of the political spectrum as opposed to central parties' supporters. In sociodemographic segments it is the younger and poorly educated who are the strongest supporters of capital punishment. It is suggested that endorsing capital punishment can be better understood as an expressive act, displaying dissatisfaction with judicial and political elites in the country.  相似文献   
876.
We report the results of Spanish and Portuguese working group (GEP) of International Society of Forensic Genetics (ISFG) Collaborative Exercise 2001-2002 on mitochondrial DNA (mtDNA) analysis. 64 laboratories from Spain, Portugal and several Latin-American countries participated in this quality control exercise. Five samples were sent to the participating laboratories, four blood stains (M1-M4) and a sample (M5) consisting of two hair shaft fragments. M4 was non-human (Felis catus) in origin; therefore, the capacity of the labs to identify the biological source of this sample was an integral part of the exercise. Some labs detected the non-human origin of M4 by carrying out immuno-diffussion techniques using antihuman serum, whereas others identified the specific animal origin by testing the sample against a set of animal antibodies or by means of the analysis of mtDNA regions (Cyt-b, 12S, and 16S genes). The results of the other three human blood stains (M1-M3) improved in relation to the last Collaborative Exercises but those related to hairs yielded a low rate of success which clearly contrasts with previous results. As a consequence of this, some labs performed additional analysis showing that the origin of this low efficiency was not the presence of inhibitors, but the low quantity of DNA present in these specific hair samples and the degradation.As a general conclusion the results emphasize the need of external proficiency testing as part of the accreditation procedure for the labs performing mtDNA analysis in forensic casework.  相似文献   
877.
Human mitochondrial DNA from 50 trios consisting of mother (M), child (C) and father (F) was PCR amplified with primers flanking the hyper-variable regions, HVR1 and HVR2. The amplified products were then fractionated under non-denaturing conditions, silver-stained and compared by single-stranded conformational polymorphism (SSCP). In all but one case, mother and child displayed identical patterns, which could be promptly distinguished from that of the father. For the remaining cases, either set of primers was sufficient to resolve the familial ties. In no instance, M displayed alleles different from those of C within each trio, demonstrating that no false exclusions occurred. The SSCP approach proved to be a robust technique suitable as a preliminary screening in cases requiring identification of multiple samples.  相似文献   
878.
The Spanish and Portuguese ISFG Working Group (GEP-ISFG) carried out a collaborative exercise in order to asses the performance of two Y chromosome STR tetraplexes, which include the loci DYS461, GATA C4, DYS437 and DYS438 (GEPY I), and DYS460, GATA A10, GATA H4 and DYS439 (GEPY II). The groups that reported correct results in all the systems were also asked to analyse a population sample in order to evaluate the informative content of these STRs in different populations. A total of 1020 males out of 13 population samples from Argentina, Brazil, Costa Rica, Macao, Mozambique, Portugal and Spain were analysed for all the loci included in the present study. Haplotype and allele frequencies of these eight Y-STRs were estimated in all samples. The lowest haplotype diversity was found in the Lara (Argentina) population (95.44%) and the highest (99.90%) in Macao (China). Pairwise haplotype analysis showed the relative homogeneity of the Iberian origin samples, in accordance with what was previously found in the European populations for other Y-STR haplotypes (http://www.ystr.org). As expected, the four non-Caucasian samples, Macao (Chinese), Mozambique (Africans), Costa Rica (Africans) and Argentina (Lara, Amerindians), show highly significant Phist values in the pairwise comparisons with all the Caucasian samples.  相似文献   
879.
According to a national survey, almost two out of every three Canadians think the federal government should be spending more to fight HIV/AIDS. The survey also found that: (a) although most Canadians know a lot about HIV/AIDS, there are some significant gaps in their knowledge; and (b) although most Canadians think HIV/AIDS is a serious problem, the vast majority do not consider themselves to be at risk for HIV infection. Few Canadians blame people for contracting HIV through sex or drug use, but many Canadians are still uncomfortable associating with people with HIV/AIDS in certain settings.  相似文献   
880.
国家自然科学基金资助项目形成的知识产权归属问题研究   总被引:2,自引:0,他引:2  
与私人投资相比 ,国家自然科学基金在资助的目的、资助的领域和投入的对象方面均有所差异。当前美国等发达国家和地区的立法对国家计划项目的成果归属所采取的放权原则值得我国借鉴。我国在确定国家自然科学基金资助项目形成的知识产权归属时应以适度放权为原则 ,以激励创新和促进利益平衡。  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