全文获取类型
收费全文 | 4458篇 |
免费 | 476篇 |
国内免费 | 3篇 |
出版年
2022年 | 22篇 |
2021年 | 83篇 |
2020年 | 55篇 |
2019年 | 69篇 |
2018年 | 88篇 |
2017年 | 58篇 |
2016年 | 113篇 |
2015年 | 199篇 |
2014年 | 217篇 |
2013年 | 225篇 |
2012年 | 330篇 |
2011年 | 307篇 |
2010年 | 183篇 |
2009年 | 169篇 |
2008年 | 264篇 |
2007年 | 275篇 |
2006年 | 243篇 |
2005年 | 250篇 |
2004年 | 239篇 |
2003年 | 187篇 |
2002年 | 179篇 |
2001年 | 67篇 |
2000年 | 46篇 |
1999年 | 55篇 |
1998年 | 55篇 |
1997年 | 26篇 |
1996年 | 25篇 |
1995年 | 26篇 |
1994年 | 25篇 |
1993年 | 21篇 |
1992年 | 43篇 |
1991年 | 33篇 |
1990年 | 40篇 |
1989年 | 38篇 |
1988年 | 38篇 |
1987年 | 41篇 |
1986年 | 26篇 |
1985年 | 30篇 |
1984年 | 30篇 |
1983年 | 37篇 |
1982年 | 35篇 |
1981年 | 40篇 |
1980年 | 23篇 |
1979年 | 22篇 |
1978年 | 28篇 |
1977年 | 32篇 |
1976年 | 30篇 |
1975年 | 19篇 |
1974年 | 31篇 |
1973年 | 22篇 |
排序方式: 共有4937条查询结果,搜索用时 15 毫秒
1.
M. Fernando Gonzalez-Zalba Chiara Ciccarelli Liviu P. Zarbo Andrew C. Irvine Richard C. Campion Bryan L. Gallagher Tomas Jungwirth Andrew J. Ferguson Joerg Wunderlich 《PloS one》2015,10(4)
We propose a novel hybrid single-electron device for reprogrammable low-power logic operations, the magnetic single-electron transistor (MSET). The device consists of an aluminium single-electron transistor with a GaMnAs magnetic back-gate. Changing between different logic gate functions is realized by reorienting the magnetic moments of the magnetic layer, which induces a voltage shift on the Coulomb blockade oscillations of the MSET. We show that we can arbitrarily reprogram the function of the device from an n-type SET for in-plane magnetization of the GaMnAs layer to p-type SET for out-of-plane magnetization orientation. Moreover, we demonstrate a set of reprogrammable Boolean gates and its logical complement at the single device level. Finally, we propose two sets of reconfigurable binary gates using combinations of two MSETs in a pull-down network. 相似文献
2.
The Invisibility of Disability: Using Dance to Shake from Bioethics the Idea of ‘Broken Bodies’ 下载免费PDF全文
Shawn H.E. Harmon 《Bioethics》2015,29(7):488-498
Complex social and ethical problems are often most effectively solved by engaging them at the messy and uncomfortable intersections of disciplines and practices, a notion that grounds the InVisible Difference project, which seeks to extend thinking and alter practice around the making, status, ownership, and value of work by contemporary dance choreographers by examining choreographic work through the lenses of law, bioethics, dance scholarship, and the practice of dance by differently‐abled dancers. This article offers a critical thesis on how bioethics has come to occupy a marginal and marginalizing role in questions about the differently‐abled body. In doing so, it has rendered the disabled community largely invisible to and in bioethics. It then defends the claim that bioethics – as a social undertaking pursued collaboratively by individuals from different disciplines – must take much better notice of the body and the embodied individual if it is to better achieve its ends, which include constructing a moral and just society. Finally, this article considers how the arts, and specifically dance (and here dance by differently‐abled dancers), provides us with rich evidence about the body and our ability to respond positively to normally ‘othered’ bodies. It concludes that greater attention to empirical evidence like that being generated in InVisible Difference will help to expand the reach and significance of bioethics, and thereby its relevance to (and consciousness of) important questions about the status of bodies and bodily differences, which must be considered as central to its ambitions. 相似文献
3.
Julie A. Eclov Qingwen Qian Rebecca Redetzke Quanhai Chen Steven C. Wu Chastity L. Healy Steven B. Ortmeier Erin Harmon Gregory C. Shearer Timothy D. O’Connell 《Journal of lipid research》2015,56(12):2297-2308
Heart failure with preserved ejection fraction (HFpEF) is half of all HF, but standard HF therapies are ineffective. Diastolic dysfunction, often secondary to interstitial fibrosis, is common in HFpEF. Previously, we found that supra-physiologic levels of ω3-PUFAs produced by 12 weeks of ω3-dietary supplementation prevented fibrosis and contractile dysfunction following pressure overload [transverse aortic constriction (TAC)], a model that resembles aspects of remodeling in HFpEF. This raised several questions regarding ω3-concentration-dependent cardioprotection, the specific role of EPA and DHA, and the relationship between prevention of fibrosis and contractile dysfunction. To achieve more clinically relevant ω3-levels and test individual ω3-PUFAs, we shortened the ω3-diet regimen and used EPA- and DHA-specific diets to examine remodeling following TAC. The shorter diet regimen produced ω3-PUFA levels closer to Western clinics. Further, EPA, but not DHA, prevented fibrosis following TAC. However, neither ω3-PUFA prevented contractile dysfunction, perhaps due to reduced uptake of ω3-PUFA. Interestingly, EPA did not accumulate in cardiac fibroblasts. However, FFA receptor 4, a G protein-coupled receptor for ω3-PUFAs, was sufficient and required to block transforming growth factor β1-fibrotic signaling in cultured cardiac fibroblasts, suggesting a novel mechanism for EPA. In summary, EPA-mediated prevention of fibrosis could represent a novel therapy for HFpEF. 相似文献
4.
5.
Plant and Soil - Agricultural practices often have persistent effects on soil physicochemical properties and soil biota, which can feedback to influence plant performance. We investigated... 相似文献
6.
7.
H. Bryan Donkin 《BMJ (Clinical research ed.)》1917,1(2926):135-136
8.
9.
Yibao Ma Yuanxi Xu Bryan D. Yestrepsky Roderick J. Sorenson Meng Chen Scott D. Larsen Hongmin Sun 《PloS one》2012,7(10)
Staphylococcus aureus is a major human pathogen and one of the more prominent pathogens causing biofilm related infections in clinic. Antibiotic resistance in S. aureus such as methicillin resistance is approaching an epidemic level. Antibiotic resistance is widespread among major human pathogens and poses a serious problem for public health. Conventional antibiotics are either bacteriostatic or bacteriocidal, leading to strong selection for antibiotic resistant pathogens. An alternative approach of inhibiting pathogen virulence without inhibiting bacterial growth may minimize the selection pressure for resistance. In previous studies, we identified a chemical series of low molecular weight compounds capable of inhibiting group A streptococcus virulence following this alternative anti-microbial approach. In the current study, we demonstrated that two analogs of this class of novel anti-virulence compounds also inhibited virulence gene expression of S. aureus and exhibited an inhibitory effect on S. aureus biofilm formation. This class of anti-virulence compounds could be a starting point for development of novel anti-microbial agents against S. aureus. 相似文献
10.