全文获取类型
收费全文 | 209篇 |
免费 | 10篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 10篇 |
2013年 | 16篇 |
2012年 | 13篇 |
2011年 | 16篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 11篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 9篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 11篇 |
1991年 | 7篇 |
1990年 | 11篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 8篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1965年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有219条查询结果,搜索用时 343 毫秒
1.
Na channel kinetics during the spontaneous heart beat in embryonic chick ventricle cells. 总被引:5,自引:5,他引:0
下载免费PDF全文
![点击此处可从《Biophysical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Using cell-attached and whole-cell recording techniques simultaneously allows the measurement of Na currents during action potentials in beating heart cells. In 7-d chick ventricle, the dynamic reversal potential for Na is 30 mV, which is 20 mV less than the reversal potential in nonbeating cells. This result implies that the spontaneous activity of heart cells raises the Na concentration at the internal face of the membrane to nearly 40 mM. Fitting the Na action currents to the Hodgkin and Huxley equations shows that patches may contain from 50 to 700 Na channels, with an average density of 23 +/- 21 per micron2. Only approximately 2% of the available Na channels are open at the peak of the Na action current. This low probability is a consequence of the channels' continual inactivation during the diastolic depolarization phase. 相似文献
2.
3.
4.
Summary Inward-rectifier channels in cardiac cells (I
K1) stabilize the resting membrane potential near the K equilibrium potential. Here we investigate the role ofI
K1 in the regulation of action potentials and link this to the influx of Ca during beating. Inward Ca current alters the open-channel probability of outwardI
K1 current. Thus Ca ions depolarize cells not only by carrying an inward current but also by blocking an outward current. 相似文献
5.
Even Amler Nelvio Cester Eleonora Salvolini Roberto Staffolani Martin Burkhard Laura Mazzanti Arnot Kotyk Carlo Romanini 《Cell biology international》1994,18(7):723-727
Placentas of women suffering from pregnancy-induced hypertension (PIH) were found to contain a greater amount of Na,K-ATPase molecules, estimated from anthroyl ouabain binding, than normotensive individuals. Both the microsomal fraction of placental cells and purified Na,K-ATPase showed an increased affinity for the specific inhibitor ouabain which, in the case of the microsomes, bound with a dissociation constant of 0.9 nM as compared with 3.4 nM in the controls. Likewise, the dissociation constant of the ouabain complex with purified Na,K-ATPase was about 3.5 times lower in the hypertensive patients. The differences are apparently caused by a different microenvironment of the ouabain-binding site, as reflected in the quantum yield of bound anthroyl ouabain. If an endogenous digitalis-like factor is present in the body fluids to regulate Na,K-ATPase activity, the present results render its role quite plausible. 相似文献
6.
Identification of a nucleo-cytoplasmic ionic pathway by osmotic shock in isolated mouse liver nuclei
Summary The observation that the nuclear envelope outer mem brane contains ion channels raises the question of whether these conductances
communicate between the cytosol and the nuclear envelope cisternae or between the cytosol and the cytoplasm. Failure to detect
large, nonselective holes using the patch-clamp technique has led to the speculation that ion channels and nuclear pores are
in fact the same.
In this paper we present evidence that the ionic channel, recorded in isolated liver nuclei with the patch-clamp configura
tion of “nucleus-attached,” spans the double membrane of the envelope, providing a direct contact between nucleoplasm and
cytoplasm. 相似文献
7.
Donatella Marazziti Lionella Palego Chiara Mazzanti Stefano Silvestri Giovanni B. Cassano 《Chronobiology international》1995,12(2):100-105
Our study aimed to investigate the possible presence of seasonal changes in platelet phenolsulfotransferase (ST) in a group of 20 healthy, drug-free subjects of both sexes and between 24 and 37 years of age. Blood samples were taken four times a year in the period immediately following the equinoxes and the solstices. The results showed that both STs underwent seasonal changes: the lowest values were found in autumn and in winter, and the highest in the summer. A positive correlation between the two STs and the length of the photoperiod was observed in winter, whereas in the spring we detected a negative correlation between the TL ST and the photoperiod length. Future studies should clarify whether platelet ST of patients with mood disorders shows a similar seasonality. 相似文献
8.
Phyllolitorin and Leu8-phyllolitorin, two nonapeptide amides from the skin of the South American frog Phyllomedusa sauvagei, are representatives of a novel bombesin subfamily, characterized by the occurrence in their molecule of a serine residue substituting the usual histidine residue at position 3 from the C-terminus. In parallel bioassay on ten different smooth muscle preparations and rat blood pressure, phyllolitorin and Leu8-phyllolitorin were virtually equiactive, but the two peptides appeared remarkably less potent that litorin in all test preparations, except the rat urinary bladder. The shape of contractions produced by the phyllolitorins and promptness of cessation of their action upon washing seem to indicate a looser binding of these peptides to their receptors and/or a more rapid inactivation, in comparison to litorin. 相似文献
9.
G Zolese P Campagnoli A Colombi L Mazzanti 《Bollettino della Società italiana di biologia sperimentale》1980,56(23):2403-2407
Electron spin resonance techniques was used to study the fluidity of intact and hemoglobin free erythrocyte membranes from patients with Duchenne muscular distrophy and from members of their family. A greater mobility of spin label motion was observed only at the surface of hemoglobin free membranes in the patients. These studies suggest alterations in lipid-protein interaction, indicating in Duchenne muscular distrophy a generalized membrane abnormality. 相似文献
10.
L Mazzanti R A Rabini G Biagini A Pugnaloni R de Pirro E Faloia V Mancini C Romanini N Cester 《European journal of biochemistry》1992,206(3):881-885
The human placenta plays an essential role in embryo development, in particular regulating the transport of ions, nutrients and immunoglobulins from the maternal to the fetal circulation. Trophoblast organization into a syncytial layer involves structural and functional steps that may be monitored and elucidated by in vitro studies. The structural stages by which the syncytial trophoblast is formed are not yet understood. In order to clarify the mechanism of trophoblast development, we studied the morphological characteristics of the syncytial trophoblast formation in culture and the functional changes (transport properties and membrane microviscosity) accompanying the structural modifications. By using both 5-nitroxystearate and 16-nitroxystearate as spin labels, we observed an initial increase in membrane order over 0-24 h of culture, which can be associated with two events: recovery of cell membranes from trypsin and initial aggregation of cytotrophoblasts. The similar behaviour of the order parameters determined with both probes indicates that membrane order changes both inside and in the outer part of the lipid bilayer. The subsequent decrease in membrane order observed at 36-48 h might be related to the process of cellular fusion. The increase in sodium/potassium pump activity in the first 24 h of culture might be an expression of cell recovery following trypsin treatment. The subsequent decrease might represent an adaptive mechanism by which metabolic energy is mainly used for morphogenetic changes. 相似文献