全文获取类型
收费全文 | 61篇 |
免费 | 0篇 |
专业分类
系统科学 | 2篇 |
现状及发展 | 16篇 |
研究方法 | 6篇 |
综合类 | 36篇 |
自然研究 | 1篇 |
出版年
2020年 | 1篇 |
2016年 | 2篇 |
2013年 | 3篇 |
2011年 | 3篇 |
2010年 | 1篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有61条查询结果,搜索用时 15 毫秒
21.
The mammalian atrium is an endocrine organ that may be involved in the control of blood pressure and extracellular fluid volume. A series of peptides, which seem to be associated with atrium-specific secretory granules, have potent natriuretic, diuretic and smooth muscle relaxant activities. Sequence determination of several of these peptides, which range from 21 to 126 amino acids long, shows that they form a family, derived from a common precursor. Rat and human complementary DNAs that encode the precursor to the various peptides, collectively called atrial natriuretic factors (ANFs), have been cloned. Nucleotide sequencing showed that the ANFs are located at the C-terminus of a polypeptide of relative molecular mass 13,000. We describe here the isolation and characterization of the corresponding human gene. Two introns interrupt the gene; one is located in the region coding for the N-terminus of the precursor and the other separates the codon for the C-terminal tyrosine from the rest of the peptide. 相似文献
22.
John L. Greenberg 《Archive for History of Exact Sciences》1996,49(4):371-391
In this article I discuss the theory of the earth's shape presented by Isaac Newton in Book III of his Principia. I show that the theory struck even the most reputable continental mathematicians of the day as incomprehensible. I examine the many obstacles to understanding the theory which the reader faced — the gaps, the underived equations, the unproven assertions, the dependence upon corollaries to practically incomprehensible theorems in Book I of the Principia and the ambiguities of these corollaries, the conjectures without explanations of their bases, the inconsistencies, and so forth. I explain why these apparent drawbacks are, historically considered, strengths of Newton's theory of the earth's shape, not weaknesses. 相似文献
23.
Gudbjartsson DF Arnar DO Helgadottir A Gretarsdottir S Holm H Sigurdsson A Jonasdottir A Baker A Thorleifsson G Kristjansson K Palsson A Blondal T Sulem P Backman VM Hardarson GA Palsdottir E Helgason A Sigurjonsdottir R Sverrisson JT Kostulas K Ng MC Baum L So WY Wong KS Chan JC Furie KL Greenberg SM Sale M Kelly P MacRae CA Smith EE Rosand J Hillert J Ma RC Ellinor PT Thorgeirsson G Gulcher JR Kong A Thorsteinsdottir U Stefansson K 《Nature》2007,448(7151):353-357
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in humans and is characterized by chaotic electrical activity of the atria. It affects one in ten individuals over the age of 80 years, causes significant morbidity and is an independent predictor of mortality. Recent studies have provided evidence of a genetic contribution to AF. Mutations in potassium-channel genes have been associated with familial AF but account for only a small fraction of all cases of AF. We have performed a genome-wide association scan, followed by replication studies in three populations of European descent and a Chinese population from Hong Kong and find a strong association between two sequence variants on chromosome 4q25 and AF. Here we show that about 35% of individuals of European descent have at least one of the variants and that the risk of AF increases by 1.72 and 1.39 per copy. The association with the stronger variant is replicated in the Chinese population, where it is carried by 75% of individuals and the risk of AF is increased by 1.42 per copy. A stronger association was observed in individuals with typical atrial flutter. Both variants are adjacent to PITX2, which is known to have a critical function in left-right asymmetry of the heart. 相似文献
24.
25.
Greenberg J 《Science news》1979,115(9):140-141
26.
Summary Elapid-toxins (-bungarotoxin,-cobratoxin and crudeBungarus caeruleus venom) do not affect the myocardial nicotinic ACh receptors of the following bivalve molluscs:Mercenaria mercenaria, Chione cancellata, Mya arenaria, Mytilus edulis, Rangia cuneata andCrassostrea virginica.Acknowledgments. This work was supported by N.I.H. grant HL-09283 to M.J.G.; it is contribution No. 102 from the Tallahassee, Sopchoppy and Gulf Coast Marine Biological Association. 相似文献
27.
Angiogenesis--the growth of new blood vessels--is a crucial force for shaping the nervous system and protecting it from disease. Recent advances have improved our understanding of how the brain and other tissues grow new blood vessels under normal and pathological conditions. Angiogenesis factors, especially vascular endothelial growth factor, are now known to have roles in the birth of new neurons (neurogenesis), the prevention or mitigation of neuronal injury (neuroprotection), and the pathogenesis of stroke, Alzheimer's disease and motor neuron disease. As our understanding of pathophysiology grows, these developments may point the way towards new molecular and cell-based therapies. 相似文献
28.
High stability of messenger RNA in growing cultured cells 总被引:45,自引:0,他引:45
J R Greenberg 《Nature》1972,240(5376):102-104
29.
M. P. Singh Y. S. Chung J. Greenberg 《Cellular and molecular life sciences : CMLS》1973,29(10):1298-1299
Résumé L'efficacité de la nitrosoguanidine (MNG) dans différents milieux de culture et tampons a été étudiée. Les résultats obtenus montrent qu'avec le temps, la fraction de cellules survivant au traitement diminue progressivement alors que la fréquence de mutation augmente dans tous les milieux. L'activité de cet agent atteint un maximum dans le milieu DM-glucose tandis que dans le tampon TM elle est à son plus bas niveau. 相似文献
30.