全文获取类型
收费全文 | 121篇 |
免费 | 0篇 |
专业分类
系统科学 | 4篇 |
理论与方法论 | 1篇 |
现状及发展 | 27篇 |
研究方法 | 10篇 |
综合类 | 77篇 |
自然研究 | 2篇 |
出版年
2016年 | 1篇 |
2013年 | 1篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 10篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 3篇 |
1967年 | 4篇 |
1965年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 31 毫秒
21.
22.
23.
Enhancing protein C interaction with thrombin results in a clot-activated anticoagulant. 总被引:2,自引:0,他引:2
Human protein C is a vitamin K-dependent plasma glycoprotein that circulates as an inactive zymogen. At the endothelial cell surface, thrombin in complex with the integral membrane protein thrombomodulin converts protein C to its active form by specific cleavage of an activation peptide. The activated form of protein C has potent anticoagulant activity as a feedback regulator of thrombin generation (reviewed in refs 4-6), and also has profibrinolytic, anti-ischaemic and anti-inflammatory properties. Protein C is effective in the treatment of model and human thrombotic diseases but, except when it has been used to treat genetic or acquired deficiencies and microvascular thrombosis, it is administered as the activated enzyme, which has a short biological half-life. We have altered two putative inhibitory acidic residues near the thrombin cleavage site, which results in a 30-fold increase in substrate utilization by alpha-thrombin. We combined these changes with a genetically altered glycoform to generate a zymogen protein C with a 60-fold increased cleavage rate by free alpha-thrombin, independent of its cofactor thrombomodulin. We show that this 'proform' of protein C, unlike the natural circulating zymogen, can be activated by thrombin generated in clotting human plasma, resulting in an inhibition of further clot formation. Our data therefore show that we have engineered a site-activated agent, which only has anticoagulant activity when significant amounts of thrombin are being generated. 相似文献
24.
Sarah S. Richardson 《Studies in history and philosophy of science》2009,40(1):14-24
Recent scholarship resuscitates the history and philosophy of a ‘left wing’ in the Vienna Circle, offering a counterhistory to the conventional image of analytic philosophy as politically conformist. This paper disputes the historical claim that early logical empiricists developed a political philosophy of science. Though some individuals in the Vienna Circle, including Rudolf Carnap and Otto Neurath, believed strongly in the importance of science to social progress, they did not construct a political philosophy of science. Both Carnap and Neurath were committed to forms of political neutralism that run strongly against a political reading of their logical empiricism. In addition, Carnap and Neurath sharply differ on precisely the subject of the place of politics in logical empiricism, throwing into question the construct of the ‘Left Vienna Circle’ as a coherent, sociohistorical, programmatic unit within the Vienna Circle. 相似文献
25.
26.
27.
Alan Richardson 《Studies in history and philosophy of science》2003,34(1):165-182
On an ordinary view of the relation of philosophy of science to science, science serves only as a topic for philosophical reflection, reflection that proceeds by its own methods and according to its own standards. This ordinary view suggests a way of writing a global history of philosophy of science that finds substantially the same philosophical projects being pursued across widely divergent scientific eras. While not denying that this view is of some use regarding certain themes of and particular time periods, this essay argues that much of the epistemology and philosophy of science in the early twentieth century in a variety of projects (neo-Kantianism, logical empiricism, pragmatism, phenomenology) looked to the then current context of the exact sciences, especially geometry and physics, not merely for its topics but also for its conceptual resources and technical tools. This suggests a more variable project of philosophy of science, a deeper connection between early twentieth-century philosophy of science and its contemporary science, and a more interesting and richer history of philosophy of science than is ordinarily offered. 相似文献
28.
de Bakker PI McVean G Sabeti PC Miretti MM Green T Marchini J Ke X Monsuur AJ Whittaker P Delgado M Morrison J Richardson A Walsh EC Gao X Galver L Hart J Hafler DA Pericak-Vance M Todd JA Daly MJ Trowsdale J Wijmenga C Vyse TJ Beck S Murray SS Carrington M Gregory S Deloukas P Rioux JD 《Nature genetics》2006,38(10):1166-1172
The proteins encoded by the classical HLA class I and class II genes in the major histocompatibility complex (MHC) are highly polymorphic and are essential in self versus non-self immune recognition. HLA variation is a crucial determinant of transplant rejection and susceptibility to a large number of infectious and autoimmune diseases. Yet identification of causal variants is problematic owing to linkage disequilibrium that extends across multiple HLA and non-HLA genes in the MHC. We therefore set out to characterize the linkage disequilibrium patterns between the highly polymorphic HLA genes and background variation by typing the classical HLA genes and >7,500 common SNPs and deletion-insertion polymorphisms across four population samples. The analysis provides informative tag SNPs that capture much of the common variation in the MHC region and that could be used in disease association studies, and it provides new insight into the evolutionary dynamics and ancestral origins of the HLA loci and their haplotypes. 相似文献
29.
Pete Richardson 《Journal of forecasting》1992,11(5):389-421
This paper examines the implications of alternative monetary policy rules for economic stabilization within Europe, using the OECD world model, INTERLINK. The results suggest that policy linkage through the Exchange Rate Mechanism will have differing effects on the effectiveness of stabilization policies depending on the nature of economic shocks. For demand shocks, the choice of monetary rule in the country of the ‘anchor’ currency is of more consequence than the flexibility of exchange rates. For supply shocks, exchange rate rigidity is likely to have more problematic effects on economic adjustment. Spillover effects are also important when the shock is felt primarily by the ‘anchor’ economy. 相似文献
30.