全文获取类型
收费全文 | 9952篇 |
免费 | 941篇 |
国内免费 | 1篇 |
出版年
2023年 | 63篇 |
2022年 | 32篇 |
2021年 | 307篇 |
2020年 | 149篇 |
2019年 | 194篇 |
2018年 | 256篇 |
2017年 | 221篇 |
2016年 | 350篇 |
2015年 | 573篇 |
2014年 | 620篇 |
2013年 | 752篇 |
2012年 | 818篇 |
2011年 | 892篇 |
2010年 | 521篇 |
2009年 | 405篇 |
2008年 | 616篇 |
2007年 | 622篇 |
2006年 | 481篇 |
2005年 | 461篇 |
2004年 | 423篇 |
2003年 | 343篇 |
2002年 | 320篇 |
2001年 | 94篇 |
2000年 | 96篇 |
1999年 | 86篇 |
1998年 | 76篇 |
1997年 | 61篇 |
1996年 | 49篇 |
1995年 | 73篇 |
1994年 | 55篇 |
1993年 | 34篇 |
1992年 | 49篇 |
1991年 | 48篇 |
1990年 | 46篇 |
1989年 | 43篇 |
1988年 | 39篇 |
1987年 | 36篇 |
1986年 | 37篇 |
1985年 | 30篇 |
1984年 | 47篇 |
1983年 | 31篇 |
1981年 | 28篇 |
1978年 | 26篇 |
1977年 | 22篇 |
1976年 | 26篇 |
1975年 | 32篇 |
1974年 | 22篇 |
1973年 | 23篇 |
1972年 | 21篇 |
1970年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Zhaolin Wang Cara Fraley Adam R. Mezo 《Bioorganic & medicinal chemistry letters》2013,23(5):1253-1256
The neonatal Fc receptor, FcRn, prolongs the half-life of IgG in the serum and represents a potential therapeutic target for the treatment of autoimmune disease. Small molecules that block the protein–protein interactions of human IgG–human FcRn may lower pathogenic autoantibodies and provide effective treatment. A novel class of quinoxalines has been discovered as antagonists of the IgG:FcRn protein–protein interaction through optimization of a hit derived from a virtual ligand-based screen. 相似文献
2.
3.
Plant and Soil - Cracks and biopores in compacted soil such as plough pans could aid deep rooting, mitigating constraints to seasonal upland use of paddy fields for rice production. This research... 相似文献
4.
Detailed methods are presented for measurement and study of in vivo mutations and in vitro mutagenesis in human lymphocytes. The methods described include preparation of conditioned medium containing interleukin-2, enumeration of mutant clones, in vitro mutagenesis, and expansion of mutant clones for further study. 相似文献
5.
A K Curran J R Rodman P R Eastwood K S Henderson J A Dempsey C A Smith 《Journal of applied physiology》2000,88(5):1840-1852
Our study was concerned with the effect of brain hypoxia on cardiorespiratory control in the sleeping dog. Eleven unanesthetized dogs were studied; seven were prepared for vascular isolation and extracorporeal perfusion of the carotid body to assess the effects of systemic [and, therefore, central nervous system (CNS)] hypoxia (arterial PO(2) = 52, 45, and 38 Torr) in the presence of a normocapnic, normoxic, and normohydric carotid body during non-rapid eye movement sleep. A lack of ventilatory response to systemic boluses of sodium cyanide during carotid body perfusion demonstrated isolation of the perfused carotid body and lack of other significant peripheral chemosensitivity. Four additional dogs were carotid body denervated and exposed to whole body hypoxia for comparison. In the sleeping dog with an intact and perfused carotid body exposed to specific CNS hypoxia, we found the following. 1) CNS hypoxia for 5-25 min resulted in modest but significant hyperventilation and hypocapnia (minute ventilation increased 29 +/- 7% at arterial PO(2) = 38 Torr); carotid body-denervated dogs showed no ventilatory response to hypoxia. 2) The hyperventilation was caused by increased breathing frequency. 3) The hyperventilatory response developed rapidly (<30 s). 4) Most dogs maintained hyperventilation for up to 25 min of hypoxic exposure. 5) There were no significant changes in blood pressure or heart rate. We conclude that specific CNS hypoxia, in the presence of an intact carotid body maintained normoxic and normocapnic, does not depress and usually stimulates breathing during non-rapid eye movement sleep. The rapidity of the response suggests a chemoreflex meditated by hypoxia-sensitive respiratory-related neurons in the CNS. 相似文献
6.
7.
Hierarchy and monophyly 总被引:1,自引:0,他引:1
8.
Eliot C. Bush Anne E. Clark Chris M. DeBoever Lillian E. Haynes Sidra Hussain Singer Ma Matthew M. McDermott Adam M. Novak John S. Wentworth 《PloS one》2012,7(11)
A significant proportion of enzymes display cooperativity in binding ligand molecules, and such effects have an important impact on metabolic regulation. This is easiest to understand in the case of positive cooperativity. Sharp responses to changes in metabolite concentrations can allow organisms to better respond to environmental changes and maintain metabolic homeostasis. However, despite the fact that negative cooperativity is almost as common as positive, it has been harder to imagine what advantages it provides. Here we use computational models to explore the utility of negative cooperativity in one particular context: that of an inhibitor binding to an enzyme. We identify several factors which may contribute, and show that acting together they can make negative cooperativity advantageous. 相似文献
9.
A Adam J Damas P Franchimont 《Comptes rendus des séances de la Société de biologie et de ses filiales》1980,174(5):856-862
A radioimmunoassay for low molecular weight (LMW) human Kininogen has been carried out. The first step was to prepare LMW Kininogen from human plasma. The proposed method allowed to get chemically pure and biologically active LMW Kininogen. This preparation was used to induce antibody. Optimal conditions for labelling and incubation were determined. This method may be applied to the assay of Kininogen in human plasma. 相似文献
10.