全文获取类型
收费全文 | 2915篇 |
免费 | 551篇 |
专业分类
各国政治 | 449篇 |
工人农民 | 228篇 |
世界政治 | 301篇 |
外交国际关系 | 145篇 |
法律 | 1389篇 |
中国政治 | 51篇 |
政治理论 | 868篇 |
综合类 | 35篇 |
出版年
2023年 | 11篇 |
2022年 | 8篇 |
2021年 | 36篇 |
2020年 | 71篇 |
2019年 | 193篇 |
2018年 | 150篇 |
2017年 | 190篇 |
2016年 | 194篇 |
2015年 | 173篇 |
2014年 | 159篇 |
2013年 | 695篇 |
2012年 | 124篇 |
2011年 | 135篇 |
2010年 | 143篇 |
2009年 | 89篇 |
2008年 | 113篇 |
2007年 | 95篇 |
2006年 | 79篇 |
2005年 | 65篇 |
2004年 | 74篇 |
2003年 | 52篇 |
2002年 | 54篇 |
2001年 | 19篇 |
2000年 | 43篇 |
1999年 | 30篇 |
1998年 | 24篇 |
1997年 | 28篇 |
1996年 | 33篇 |
1995年 | 21篇 |
1994年 | 27篇 |
1993年 | 23篇 |
1992年 | 21篇 |
1991年 | 31篇 |
1990年 | 24篇 |
1989年 | 17篇 |
1988年 | 17篇 |
1987年 | 14篇 |
1986年 | 27篇 |
1985年 | 21篇 |
1984年 | 18篇 |
1983年 | 19篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 14篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1975年 | 4篇 |
1974年 | 7篇 |
1971年 | 5篇 |
排序方式: 共有3466条查询结果,搜索用时 15 毫秒
61.
Yi‐Hong Liao BS Jae‐Sang Hyun PhD Michael Feller MS Tyler Bell PhD Ian Bortins BS James Wolfe MS David Baldwin PhD Song Zhang PhD 《Journal of forensic sciences》2021,66(1):112-128
The forensic science community raised the need for improved evidence recognition, collection, and visualization analytical instrumentation for field and laboratory use. While the 3D optical techniques for imaging static objects have been extensively studied, there is still a major gap between current knowledge and collecting high‐quality footwear and tire impression evidence. Among optical means for 3D imaging, digital fringe projection (DFP) techniques reconstruct 3D shape from phase information, achieving camera‐pixel spatial resolution. This paper presents a high‐resolution 3D imaging technology using DFP techniques dedicated to footwear and tire impression capture. We developed fully automated software algorithms and a graphical user interface (GUI) that allow anyone without training to operate for high‐quality 3D data capture. We performed accuracy evaluations and comparisons comparing with the commercial high‐end 3D scanner and carried out qualitative tests for various impressions comparing with the current practices. Overall, our technology achieves similar levels of accuracy and resolution with a high‐end commercially available 3D scanner, while having the merits of being (1) more affordable; (2) much easier to operate; and (3) more robust. Compared with the current practice of casting, our technology demonstrates its superiority because it (1) is non‐destructive; (2) collects more evidence detail than casts, especially when an impression is fragile; (3) requires less time and money to collect each piece of evidence; and (4) results in a digital file that can easily be shared with other examiners. 相似文献
62.
63.
Darrell O. Ricke Ph.D. Philip Fremont‐Smith M.S. James Watkins B.S. Sara Stankiewicz M.S. Tara Boettcher B.S. Eric Schwoebel Ph.D. 《Journal of forensic sciences》2019,64(5):1468-1474
High‐throughput sequencing (HTS) of large panels of single nucleotide polymorphisms (SNPs) provides an alternative or complimentary approach to short tandem repeats (STRs) panels for the analysis of complex DNA mixture forensic samples. For STRs, methods to estimate individual contribution concentrations compare capillary electrophoresis peak heights, peak areas, or HTS allele read counts within a mixture. This article introduces three approaches (mean, median, and slope methods) for estimating individual DNA contributions to forensic mixtures for HTS/massively parallel sequencing (MPS) SNP panels. For SNPs, the major:minor allele ratios or counts, unique to each contributor, were compared to estimate contributor proportion within the mixture using the mean, median, and slope intercept for these alleles. The estimates for these three methods were typically within 5% of planned experimental contributions for defined mixtures. 相似文献
64.
The last decade has seen remarkable growth in the field of behavioral public administration, both in practice and in academia. In both domains, applications of behavioral science to policy problems have moved forward at breakneck speed; researchers are increasingly pursuing randomized behavioral interventions in public administration contexts, editors of peer-reviewed academic journals are showing greater interest in publishing this work, and policy makers at all levels are creating new initiatives to bring behavioral science into the public sector. However, because the expansion of the field has been so rapid, there has been relatively little time to step back and reflect on the work that has been done and to assess where the field is going in the future. It is high time for such reflection: where is the field currently on track, and where might it need course correction? 相似文献
65.
66.
67.
68.
69.
Anna Arabindan‐Kesson 《Women's history review》2013,22(3):501-503
Abstract In an effort to popularise the gas stove, boost sales and minimize the genuine and perceived dangers of using this volatile domestic appliance, late Victorian gas managers and stove manufacturers employed female cookery teachers to perform public demonstrations at trade exhibitions throughout the country. Eventually, these women comprised a special department of gas sales, calling directly on customers in their homes to offer personal instruction in the proper use and care of gas stoves. Part social workers, part salesgirls, the ‘lady demons’, short for lady demonstrators, moved between the traditionally gendered separate spheres of work and home, consciously constructing a professional image that reconciled the social tensions of this new occupation. They offer an early example of women's entrance into the corporate business world, the feminisation of consumption, and the combination of customer service with social welfare. 相似文献
70.