全文获取类型
收费全文 | 1929篇 |
免费 | 67篇 |
专业分类
各国政治 | 162篇 |
工人农民 | 59篇 |
世界政治 | 112篇 |
外交国际关系 | 64篇 |
法律 | 1305篇 |
中国政治 | 10篇 |
政治理论 | 273篇 |
综合类 | 11篇 |
出版年
2020年 | 35篇 |
2019年 | 38篇 |
2018年 | 53篇 |
2017年 | 67篇 |
2016年 | 62篇 |
2015年 | 32篇 |
2014年 | 46篇 |
2013年 | 223篇 |
2012年 | 50篇 |
2011年 | 73篇 |
2010年 | 45篇 |
2009年 | 46篇 |
2008年 | 55篇 |
2007年 | 55篇 |
2006年 | 55篇 |
2005年 | 55篇 |
2004年 | 53篇 |
2003年 | 62篇 |
2002年 | 49篇 |
2001年 | 64篇 |
2000年 | 53篇 |
1999年 | 49篇 |
1998年 | 17篇 |
1997年 | 16篇 |
1996年 | 21篇 |
1995年 | 12篇 |
1994年 | 14篇 |
1993年 | 13篇 |
1992年 | 29篇 |
1991年 | 32篇 |
1990年 | 37篇 |
1989年 | 38篇 |
1988年 | 35篇 |
1987年 | 26篇 |
1986年 | 35篇 |
1985年 | 28篇 |
1984年 | 20篇 |
1983年 | 18篇 |
1982年 | 13篇 |
1981年 | 22篇 |
1980年 | 12篇 |
1979年 | 20篇 |
1978年 | 22篇 |
1977年 | 16篇 |
1973年 | 11篇 |
1971年 | 18篇 |
1970年 | 17篇 |
1969年 | 12篇 |
1968年 | 17篇 |
1967年 | 12篇 |
排序方式: 共有1996条查询结果,搜索用时 15 毫秒
41.
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
42.
43.
44.
We simulate effects of two recessions on Massachusetts municipalities in light of their relative dependence on state aid, capacity to increase property taxes under Proposition 2½ constraints, growth, and nondiscretionary costs. We also explore the efficacy of local government stabilization funds in light of current literature on stabilization funds, slack resources in general, and the state–local fiscal relationship. We found substantial variance in Massachusetts municipalities' recession readiness. Fifty‐five (16 percent) municipalities have insufficient resources to weather a severe recession scenario without significant sacrifice due to reliance on state grants‐in‐aid, low property tax revenue growth, erosion of property tax revenue increments by increases in nondiscretionary expenditures, and inadequate stabilization funds. 相似文献
45.
46.
Terezie Cernosek B.S. Kevin E. Eckert M.Sc. David O. Carter Ph.D. Katelynn A. Perrault Ph.D. 《Journal of forensic sciences》2020,65(1):134-143
Volatile organic compounds (VOCs) are by-products of cadaveric decomposition and are responsible for the odor associated with decomposing remains. The direct link between VOC production and individual postmortem microbes has not been well characterized experimentally. The purpose of this study was to profile VOCs released from three postmortem bacterial isolates (Bacillus subtilis, Ignatzschineria indica, I. ureiclastica) using solid-phase microextraction arrow (SPME Arrow) and gas chromatography–mass spectrometry (GC-MS). Species were inoculated in headspace vials on Standard Nutrient Agar and monitored over 5 days at 24°C. Each species exhibited a different VOC profile that included common decomposition VOCs. VOCs exhibited upward or downward temporal trends over time. Ignatzschineria indica produced a large amount of dimethyldisulfide. Other compounds of interest included alcohols, aldehydes, aromatics, and ketones. This provides foundational data to link decomposition odor with specific postmortem microbes to improve understanding of underlying mechanisms for decomposition VOC production. 相似文献
47.
48.
49.
T Karlsmark H K Thomsen L Danielsen O Aalund O Nielsen K G Nielsen I K Genefke 《Forensic science international》1988,39(2):175-188
In order to establish pathological evidence in dermis for distinguishing between sequelae of electrical torture and those of other superficial injuries, the skin of eleven fully anaesthetized Danish Landrace pigs have been exposed to heat and electrical energy from either 50 Hz alternating current (a.c.) or direct current (d.c.) via 12 mm large contact knobs or via a pointed 0.5 mm large electrode (only 50 Hz a.c.). The lesions have been examined from 1 to 126 days after the injury. While heat lesions exposed to energy lower than 60 joule only gave minor changes, heat lesions exposed to more than 60 joule showed changes in both collagen fibres (basophilic or eosinophilic fibres without any birefringence or coarse cross-striation in polarized light, respectively) and dermal cells (granular cytoplasm). Areas exposed to 50 Hz a.c. via 0.5 mm. electrode showed basophilic collagen fibres and in a few biopsies on day 7 calcium salts on collagen fibres. Using 12 mm large electrodes the changes were minor, but basophilic and eosinophilic collagen fibres with no birefringence or with fine/coarse cross-striation respectively were seen. Even cells with 'vesicular nuclei' were seen on day 1 and 2 after the injury. The changes in the anode area showed resemblance to that of heat lesions (basophilic collagen fibres). Eosinophilic collagen fibres with fine densely spaced cross-striation in polarized light and 'vesicular nuclei' as well as collagen fibres with calcium salts were seen in the cathode lesions. It is concluded that the dermal changes in the cathode area are specific for electrical injury from day 1 to 14. However, earlier studies have demonstrated dermal changes specific for electrical injury at day 0 and the presence of calcified collagen fibres up to 2 months after injury. The dermal changes in anode lesions were non specific and could not be differentiated from those found in heat lesions. Alternating current lesions (50 Hz) were specific from day 1 to day 7, when the pointed electrode was used, but only in a few days when the energy was transferred via the 12-mm electrodes. 相似文献
50.
Erin O’Connor 《澳大利亚女权主义者研究》2018,33(98):530-547
ABSTRACTThis inquiry analyses the rhetoric of intentionally unfinished fashion contained in the collections from Céline as designed by Phoebe Philo and explicates the implications of this approach to fashion as a feminist text. Shoshana Felman’s seductive promise of speech, modified with insights from Paul de Man’s theory of autobiography as both giving face and defacement, is applied to Philo’s ‘new minimalism’ in order to highlight its appeal to modern female audiences. Using insights from the philosophy of Jacques Derrida, I examine ways in which wearers may seek to create a signature citationality via clothing that produces its own ‘unwriting’ therefore allowing the wearer to believe she inscribes her own iteration while maintaining control. Wearers are offered the chance to identify with a designer who is enlightened beyond fast and flashy fashion while hinting at the notion of the clothing having the substantialising effect that language has (instead of representational). Through this examination, clothing is shown to be a decision, and clothing is also shown to be a fiction. These decisions and fictions are open to failure; yet Felman offers that this failure acts as an opening remaining inadvertent or unacknowledged. Philo's designs invite an exploration of clothing as performative rhetoric. 相似文献