全文获取类型
收费全文 | 290篇 |
免费 | 57篇 |
国内免费 | 1篇 |
出版年
2021年 | 4篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 14篇 |
2012年 | 10篇 |
2011年 | 8篇 |
2010年 | 7篇 |
2009年 | 11篇 |
2008年 | 4篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 14篇 |
2002年 | 13篇 |
2001年 | 10篇 |
2000年 | 16篇 |
1999年 | 15篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1994年 | 5篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1981年 | 3篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1973年 | 3篇 |
1972年 | 9篇 |
1971年 | 3篇 |
1970年 | 7篇 |
1969年 | 4篇 |
1968年 | 5篇 |
1967年 | 2篇 |
1966年 | 2篇 |
1965年 | 3篇 |
1964年 | 3篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1948年 | 2篇 |
排序方式: 共有348条查询结果,搜索用时 15 毫秒
1.
2.
Interaction between the Effects of Inside and Outside Na and K on Bullfrog Skin Potential 总被引:2,自引:1,他引:1
Daniel E. Leb Charles Edwards Barry D. Lindley T. Hoshiko with the technical assistance of James A. Dugan 《The Journal of general physiology》1965,49(2):309-320
The composition of the solution bathing one border of the isolated frog skin affects the response of the potential across the skin to changes in the composition of the solution bathing the opposite border. Increasing the K concentration of the inside (corium) bathing solution decreased the sensitivity of the potential to a change in outside Na concentration. Decreasing the outside Na concentration decreased the sensitivity of the potential to a change in inside K concentration. Increasing the total ionic strength of the outside bathing solution or of both bathing solutions decreased the sensitivity of the potential to a change in outside Na concentration. 相似文献
3.
Evolution and Extinction of Transposable Elements in Mendelian Populations 总被引:8,自引:2,他引:6 下载免费PDF全文
A model of the evolution of a transposable element family in a Mendelian host population is proposed that incorporates heritable phenotypic mutations in the elements. The temporal behavior of the numbers of mutant and wild-type elements is studied, and the expected extinction time of the transposable element family is examined. Our results indicate that, if the mutant can be transposed equally well in the presence of the wild type, then it can be expected to be found in preponderance, whereas elements, such as retroviruses, where the transposing genome and its phenotypic expression are coupled, may be characterized by a low mutant frequency. 相似文献
4.
Barry D. Lindley 《The Journal of general physiology》1969,53(4):427-449
The suitability of frog skin glands as a model for the study of secretory mechanisms in exocrine glands was explored. Periodic voltage clamp was used to determine continually the short-circuit current, chord conductance, and electromotive force of frog skin during neural and pharmacological activation of the skin glands. Both the chord conductance and the short-circuit current increased with glandular activation; the temporal dissociation of these increases suggests that there are at least two separate components to the secretory response. The sensitivity of the secretory electrical changes to changes in the ionic composition of the bathing solutions supports the notion of electrogenic chloride active transport as being basic to the activity of the exocrine glands. 相似文献
5.
The Effects of Alkali Metal Cations and Common Anions on the Frog Skin Potential 总被引:8,自引:6,他引:2 下载免费PDF全文
The effects on the potential difference across isolated frog skin (R. catesbeiana, R. pipiens) of changing the ionic composition of the bathing solutions have been examined. Estimates of mean values and precision are presented for the potential changes produced by substituting other alkali metal cations for Na at the outside border and for K at the inside border. In terms of ability to mimic Na at the outside border of bullfrog skin, the selectivity order is Li > Rb, K, Cs; at the outside border of leopard frog skin, Li > Cs, K, Rb. In terms of ability to mimic K at the inside border of bullfrog and leopard frog skin: Rb > Cs > Li > Na. Orders of anion selectivity in terms of sensitivity of the potential for the outside border of bullfrog skin are Br > Cl > NO3 > I > SO4, isethionate and of leopard frog skin are Br, Cl > I, NO3, SO4. An effect of the solution composition (ionic strength?) on the apparent Na-K selectivity of the outside border is described. The results of the investigation have been interpreted and discussed in terms of the application of the constant field equation to the Koefoed-Johnsen-Ussing frog skin model. These observations may be useful in constructing and testing models of biological ionic selectivity. 相似文献
6.
Modified carbon flux during oxygen limited growth of Corynebacterium glutamicum and the consequences for amino acid overproduction 总被引:1,自引:0,他引:1
Summary The amino acid producing bacterium Corynebacterium glutamicum accumulated lactate, succinate and acetate under oxygen-limited growth conditions. Significant restructuring of carbon flux through the central metabolic pathways occurred with a notable decrease in pentose pathway flux and the operation of the TCA cycle in a reductive mode. Simultaneous consumption of residual sugar and organic acids took place when oxygen sufficient conditions were restored though amino acids yields were significantly perturbed. 相似文献
7.
Irina Zaitseva Vjacheslav Zaitsev Graeme Card Kirill Moshkov Benjamin Bax Adam Ralph Peter Lindley 《Journal of biological inorganic chemistry》1996,1(1):15-23
The X-ray structure of human serum ceruloplasmin has been solved at a resolution of 3.1?Å. The structure reveals that the molecule is comprised of six plastocyanin-type domains arranged in a triangular array. There are six copper atoms; three form a trinuclear cluster sited at the interface of domains 1 and 6, and there are three mononuclear sites in domains 2, 4 and 6. Each of the mononuclear coppers is coordinated to a cysteine and two histidine residues, and those in domains 4 and 6 also coordinate to a methionine residue; in domain 2, the methionine is replaced by a leucine residue which may form van der Waals type contacts with the copper. The trinuclear centre and the mononuclear copper in domain 6 form a cluster essentially the same as that found in ascorbate oxidase, strongly suggesting an oxidase role for ceruloplasmin in the plasma. 相似文献
8.
Control of the shift from homolactic acid to mixed-acid fermentation in Lactococcus lactis: predominant role of the NADH/NAD+ ratio. 总被引:4,自引:0,他引:4 下载免费PDF全文
C Garrigues P Loubiere N D Lindley M Cocaign-Bousquet 《Journal of bacteriology》1997,179(17):5282-5287
During batch growth of Lactococcus lactis subsp. lactis NCDO 2118 on various sugars, the shift from homolactic to mixed-acid metabolism was directly dependent on the sugar consumption rate. This orientation of pyruvate metabolism was related to the flux-controlling activity of glyceraldehyde-3-phosphate dehydrogenase under conditions of high glycolytic flux on glucose due to the NADH/NAD+ ratio. The flux limitation at the level of glyceraldehyde-3-phosphate dehydrogenase led to an increase in the pool concentrations of both glyceraldehyde-3-phosphate and dihydroxyacetone-phosphate and inhibition of pyruvate formate lyase activity. Under such conditions, metabolism was homolactic. Lactose and to a lesser extent galactose supported less rapid growth, with a diminished flux through glycolysis, and a lower NADH/NAD+ ratio. Under such conditions, the major pathway bottleneck was most probably at the level of sugar transport rather than glyceraldehyde-3-phosphate dehydrogenase. Consequently, the pool concentrations of phosphorylated glycolytic intermediates upstream of glyceraldehyde-3-phosphate dehydrogenase decreased. However, the intracellular concentration of fructose-1,6-bisphosphate remained sufficiently high to ensure full activation of lactate dehydrogenase and had no in vivo role in controlling pyruvate metabolism, contrary to the generally accepted opinion. Regulation of pyruvate formate lyase activity by triose phosphates was relaxed, and mixed-acid fermentation occurred (no significant production of lactate on lactose) due mostly to the strong inhibition of lactate dehydrogenase by the in vivo NADH/NAD+ ratio. 相似文献
9.
J G Grossmann M Neu E Pantos F J Schwab R W Evans E Townes-Andrews P F Lindley H Appel W G Thies S S Hasnain 《Journal of molecular biology》1992,225(3):811-819
X-ray solution scattering has been used for studying the structural changes that take place upon uptake and release of iron from serum and chicken ovo-transferrin and human lactoferrin. In the case of chicken ovo-transferrin, data have been obtained for both the intact protein and the isolated N and C-lobes with and without iron. These studies reveal that both lobes undergo a change that is consistent with an opening of the inter-domain cleft when iron is removed from the protein. We suggest that the conformational change of the protein increases the specificity of receptor binding and that the closed configuration of the iron-loaded protein is one, or perhaps the, decisive step in the mechanism for receptor-mediated endocytosis. 相似文献