全文获取类型
收费全文 | 4055篇 |
免费 | 137篇 |
专业分类
各国政治 | 143篇 |
工人农民 | 134篇 |
世界政治 | 266篇 |
外交国际关系 | 138篇 |
法律 | 2782篇 |
中国政治 | 37篇 |
政治理论 | 673篇 |
综合类 | 19篇 |
出版年
2021年 | 28篇 |
2020年 | 51篇 |
2019年 | 60篇 |
2018年 | 77篇 |
2017年 | 102篇 |
2016年 | 92篇 |
2015年 | 75篇 |
2014年 | 85篇 |
2013年 | 323篇 |
2012年 | 94篇 |
2011年 | 121篇 |
2010年 | 90篇 |
2009年 | 93篇 |
2008年 | 115篇 |
2007年 | 96篇 |
2006年 | 119篇 |
2005年 | 94篇 |
2004年 | 104篇 |
2003年 | 100篇 |
2002年 | 96篇 |
2001年 | 192篇 |
2000年 | 136篇 |
1999年 | 108篇 |
1998年 | 43篇 |
1997年 | 49篇 |
1996年 | 39篇 |
1995年 | 54篇 |
1994年 | 47篇 |
1993年 | 56篇 |
1992年 | 84篇 |
1991年 | 89篇 |
1990年 | 80篇 |
1989年 | 67篇 |
1988年 | 86篇 |
1987年 | 83篇 |
1986年 | 102篇 |
1985年 | 113篇 |
1984年 | 89篇 |
1983年 | 81篇 |
1982年 | 41篇 |
1981年 | 36篇 |
1979年 | 40篇 |
1978年 | 33篇 |
1975年 | 35篇 |
1974年 | 49篇 |
1973年 | 26篇 |
1972年 | 27篇 |
1971年 | 32篇 |
1970年 | 33篇 |
1968年 | 35篇 |
排序方式: 共有4192条查询结果,搜索用时 0 毫秒
971.
The authors have developed a method for molecular-genetic analysis of DNA from isolated cells for the purpose of forensic medical diagnostics. The method is based on the use of the laser capture microdissection (LCM) technology in combination with typing of mitochondrial DNA. Optimization of the conditions for amplification of polymorphic mtDNA loci in preparations containing minimal amounts of the genetic material was accomplished at the initial stage of the work. To this effect, the two-round polymerase chain reaction was employed that allowed the amplified material to be accumulated in the amount sufficient for sequenation. At the next stages, the system thus obtained was tested on the cell model (using isolated cells of human buccal epithelium). It was shown that the proposed method is suitable for the analysis of specific mtDNA characteristics in a single human cell. 相似文献
972.
Shormanov VK Duritsyn EP Prosvetova AP Kim AV Iliushina TN 《Sudebno-meditsinskaia ekspertiza》2011,54(6):27-29
The objective of the present work was to study the distribution of tetramethylthiuram disulfide (TMTD) in the body of warm-blooded animals as exemplified by white rats. TMTD was administered intragastrically and detected in the unaltered form in other internal organs. It was found to accumulate in the largest amounts in the gastric contents, kidneys, and urine. 相似文献
973.
An original test-system for the preliminary quantitative and qualitative evaluation of isolated DNA is proposed by the polymerase chain reaction in real time (PCR-RT) based on the TaqMan technology. This test-system permits to simultaneously measure the amount of DNA in the sample, identify the genetic gender, and detect PCR inhibitors. The method has been approbated in the practical work of forensic medical experts. 相似文献
974.
This study investigated the value of antemortem (AM) and postmortem (PM) radiographs of the claviculae and C3-T4 vertebrae to identify skeletons of missing U.S. soldiers from past military operations. In total, 12 field-recovered skeletons and AM chest radiographs of 1460 individuals were used. For each skeleton, examiners analyzed an array of AM chest radiographs (up to 1000 individuals) and attempted to identify the correct PM/AM radiographic match. When examiners were able to compare all images within a single test, only true-positive identifications were made. When AM radiographs were presented one-at-a-time, in sequential order, and without examiners having knowledge of array size, erroneous identifications resulted but they were almost exclusively made by untrained examiners (accuracy = 35% vs. 90% for trained examiners). This study demonstrates the value of chest radiographs for the identification of disarticulated and even eroded skeletons, but only when methods are wielded by trained examiners. 相似文献
975.
The successful identification of human skeletal remains relies on proven diagnostic techniques for sex determination. This research utilized 608 individuals from South Africa (420 men, 188 women) to conduct a blind nonmetric determination of sex from three features of the distal humerus: olecranon fossa shape, angle of the medial epicondyle, and trochlear extension. A scoring system between males and females was implemented, and the aggregate score of the three features determined the estimated sex of the skeletal element in question. With all features combined, black and white South Africans were categorized successfully as either male or female 75.5% (77% accuracy rate for females, 74% accuracy rate for males). This classification rate is lower than what was found in previous studies, but suggests that characteristics of the distal humerus are still quite valuable when estimating skeletal sex. More research is needed to assess reasons for the differential expression of these traits in different populations and to determine whether the method is nonpopulation specific. 相似文献
976.
977.
Self-control theory (Gottfredson and Hirschi 1990) argues that individuals with similar attributes tend to ‘end up together’ (i.e., homophily) because of the tendency to select
friends based on self-control. Studies documenting homophily in peer groups interpret the correlation between self-control,
peer delinquency, and self-reported delinquency as evidence that self-control is an influential factor in friendship formation.
However, past studies are limited because they do not directly test the hypothesis that self-control influences friendship
selection, nor do they account for other mechanisms that may influence decisions. As a result, it is unclear whether the correlation
between individual and peer behavior is the result of selection based on self-control or alternative mechanisms. To address
this gap in the literature this study employs exponential random graph modeling to test hypotheses derived from self-control
theory using approximately 63,000 respondents from 59 schools from the National Longitudinal Survey of Adolescent Health (Add
Health). In contrast to the predictions made by Gottfredson and Hirschi (1990), and the conclusions drawn from prior research, there is little evidence that self-control influences friendship selection.
The findings are embedded in past work on the relationship between self-control and peer relationships, and implications for
future research are discussed. 相似文献
978.
Albert Jacob Meijer 《Public administration review》2011,71(4):598-607
Research on and practical attention for the coproduction of public services is increasing. Coproduction is seen as a way to strengthen the quality and legitimacy of public service and reduce costs. Scholarship on coproduction of public services repeatedly ignores the role of the new media. This is surprising since many proponents highlight its potential for changing traditional, government‐centric approaches to delivering public services. This article shows that digital communities form an important addition to the government‐centric form of public service provision since they foster both an exchange of experiential information and social‐emotional support. 相似文献
979.
Jos C. N. Raadschelders 《Public administration review》2011,71(6):916-924
What should be done to advance the study of public administration? A strong argument is advanced by outgoing PAR managing editor Jos C. N. Raadschelders that the field benefits significantly from greater attention to ontology and epistemology. To be sure, empirical, evidence‐based research has its place, but its basis and the meaning of findings seldom are questioned. Why? Many public administration scholars seek “scientificness” through a disciplinary type of methodology. However, working within an inherently interdisciplinary field, public administration scholars cannot reduce the complex, wicked problems of society and government to mere empirical measurement. The author lays out five critical challenges confronting today’s public administration—both its study and research—requiring the field’s urgent attention in order to meet the comprehensive and rapidly expanding needs of specialists and generalists, practitioners and academicians, as well as the general public. 相似文献
980.