全文获取类型
收费全文 | 355篇 |
免费 | 14篇 |
专业分类
369篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 20篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 24篇 |
2014年 | 21篇 |
2013年 | 28篇 |
2012年 | 21篇 |
2011年 | 25篇 |
2010年 | 16篇 |
2009年 | 16篇 |
2008年 | 21篇 |
2007年 | 17篇 |
2006年 | 19篇 |
2005年 | 10篇 |
2004年 | 13篇 |
2003年 | 14篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有369条查询结果,搜索用时 0 毫秒
291.
Jayasankar Dheiksha Jayasankar Varsha Subramanian Jayasankar 《In vitro cellular & developmental biology. Plant》2022,58(3):407-415
In Vitro Cellular & Developmental Biology - Plant - The global food crisis is an issue affecting 1 billion people worldwide—it is critical that a solution be developed to provide the... 相似文献
292.
Tiane Chen Hetal S. Kocinsky Boyoung Cha Rakhilya Murtazina Jianbo Yang C. Ming Tse Varsha Singh Robert Cole Peter S. Aronson Hugo de Jonge Rafiquel Sarker Mark Donowitz 《The Journal of biological chemistry》2015,290(4):1952-1965
The epithelial brush-border Na+/H+ exchanger NHE3 is acutely inhibited by cGKII/cGMP, but how cGKII inhibits NHE3 is unknown. This study tested the hypothesis that cGMP inhibits NHE3 by phosphorylating it and altering its membrane trafficking. Studies were carried out in PS120/NHERF2 and in Caco-2/Bbe cells overexpressing HA-NHE3 and cGKII, and in mouse ileum. NHE3 activity was measured with 2′,7′-bis(carboxyethyl)-S-(and 6)carboxyfluorescein acetoxy methylester/fluorometry. Surface NHE3 was determined by cell surface biotinylation. Identification of NHE3 phosphorylation sites was by iTRAQ/LC-MS/MS with TiO2 enrichment and immunoblotting with specific anti-phospho-NHE3 antibodies. cGMP/cGKII rapidly inhibited NHE3, which was associated with reduced surface NHE3. cGMP/cGKII increased NHE3 phosphorylation at three sites (rabbit Ser554, Ser607, and Ser663, equivalent to mouse Ser552, Ser605, and Ser659), all of which had to be present at the same time for cGMP to inhibit NHE3. NHE3-Ser663 phosphorylation was not necessary for cAMP inhibition of NHE3. Dexamethasone (4 h) stimulated wild type NHE3 activity and increased surface expression but failed to stimulate NHE3 activity or increase surface expression when NHE3 was mutated to either S663A or S663D. We conclude that 1) cGMP inhibition of NHE3 is associated with phosphorylation of NHE3 at Ser554, Ser607, and Ser663, all of which are necessary for cGMP/cGKII to inhibit NHE3. 2) Dexamethasone stimulates NHE3 by phosphorylation of a single site, Ser663. The requirement for three phosphorylation sites in NHE3 for cGKII inhibition, and for phosphorylation of one of these sites for dexamethasone stimulation of NHE3, is a unique example of regulation by phosphorylation. 相似文献
293.
Meghana Gupta Xiaojun Qi Varsha Thakur Danny Manor 《The Journal of biological chemistry》2014,289(24):17195-17202
Rho GTPases are molecular “switches” that cycle between “on” (GTP-bound) and “off” (GDP-bound) states and regulate numerous cellular activities such as gene expression, protein synthesis, cytoskeletal rearrangements, and metabolic responses. Dysregulation of GTPases is a key feature of many diseases, especially cancers. Guanine nucleotide exchange factors (GEFs) of the Dbl family are activated by mitogenic cell surface receptors and activate the Rho family GTPases Cdc42, Rac1, and RhoA. The molecular mechanisms that regulate GEFs from the Dbl family are poorly understood. Our studies reveal that Dbl is phosphorylated on tyrosine residues upon stimulation by growth factors and that this event is critical for the regulated activation of the GEF. These findings uncover a novel layer of complexity in the physiological regulation of this protein. 相似文献
294.
Awwad HO Iyer V Rosenfeld JL Millman EE Foster E Moore RH Knoll BJ 《Experimental cell research》2007,313(12):2586-2596
Phosphatidylinositol 3-kinase inhibitors have been shown to affect endocytosis or subsequent intracellular sorting in various receptor systems. Agonist-activated beta(2)-adrenergic receptors undergo desensitization by mechanisms that include the phosphorylation, endocytosis and degradation of receptors. Following endocytosis, most internalized receptors are sorted to the cell surface, but some proportion is sorted to lysosomes for degradation. It is not known what governs the ratio of receptors that recycle versus receptors that undergo degradation. To determine if phosphatidylinositol 3-kinases regulate beta(2)-adrenergic receptor trafficking, HEK293 cells stably expressing these receptors were treated with the phosphatidylinositol 3-kinase inhibitors LY294002 or wortmannin. We then studied agonist-induced receptor endocytosis and postendocytic sorting, including recycling and degradation of the internalized receptors. Both inhibitors amplified the internalization of receptors after exposure to the beta-agonist isoproterenol, which was attributable to the sorting of a significant fraction of receptors to an intracellular compartment from which receptor recycling did not occur. The initial rate of beta(2)-adrenergic receptor endocytosis and the default rate of receptor recycling were not significantly altered. During prolonged exposure to agonist, LY294002 slowed the degradation rate of beta(2)-adrenergic receptors and caused the accumulation of receptors within rab7-positive vesicles. These results suggest that phosphatidylinositol 3-kinase inhibitors (1) cause a misrouting of beta(2)-adrenergic receptors into vesicles that are neither able to efficiently recycle to the surface nor sort to lysosomes, and (2) delays the movement of receptors from late endosomes to lysosomes. 相似文献
295.
We examined pollen of all five species of Olinia, the only genus of Oliniaceae (Myrtales), an endemic African family. Olinia pollen is heteropolar with one pole colpate and the other heterocolpate. Restriction of pseudocolpi to one polar face, hence, half pseudocolpi, the inequality of the two polar faces, and the unequal distribution of the colpus segments across the modal plane, are features that distinguish Olinia from all other Myrtales. 相似文献
296.
Edward L. Vezey Varsha P. Shah John J. Skvarla 《Plant Systematics and Evolution》1992,181(3-4):245-254
We present a key synthesizing pollen-sculpture terminology for grains having perforations or lumina of any size and spatial distribution. The key uses quantitative criteria to distinguish five non-overlapping qualitative terms (reticulate, microreticulate, foveolate, scrobiculate, and punctate). In addition, the range of quantitative variation encompassed by these qualitative terms is highlighted, including ways to express and compare that variation using computerized image analysis of SEM micrographs. Finally, a mathematical analysis combined with image-analysis measurements is used to explore the relationships between the terms outlined above and two closely related terms, tectate and semitectate. 相似文献
297.
The exponential decay model of a neuron has been analyzed using the “random walk” approach of stochastic processes and an
“absorbing barrier” solution is obtained forg
T
(s)—the Laplace transform of the output pulse interval density function. An expression for the mean output frequency is derived
from this and a variety of input-output curves plotted which show frequency threshold effects in single neurons. Our results
are compared with those of other authors obtained by computer simulation techniques, and the significance of these results
discussed with reference to the possible behavior of networks constructed of such neuron units. 相似文献
298.
299.
Ghosh Pratik Bhakta Swarnav Bhattacharya Manojit Sharma Ashish Ranjan Sharma Garima Lee Sang-Soo Chakraborty Chiranjib 《International journal of peptide research and therapeutics》2021,27(2):1149-1166
International Journal of Peptide Research and Therapeutics - Helicobacter pylori is a highly potential pathogen to colonize in the human stomach. This bacterial strain is now alarming serious... 相似文献
300.
Soriano SF Hons M Schumann K Kumar V Dennier TJ Lyck R Sixt M Stein JV 《Journal of immunology (Baltimore, Md. : 1950)》2011,187(5):2356-2364
Migrating lymphocytes acquire a polarized phenotype with a leading and a trailing edge, or uropod. Although in vitro experiments in cell lines or activated primary cell cultures have established that Rho-p160 coiled-coil kinase (ROCK)-myosin II-mediated uropod contractility is required for integrin de-adhesion on two-dimensional surfaces and nuclear propulsion through narrow pores in three-dimensional matrices, less is known about the role of these two events during the recirculation of primary, nonactivated lymphocytes. Using pharmacological antagonists of ROCK and myosin II, we report that inhibition of uropod contractility blocked integrin-independent mouse T cell migration through narrow, but not large, pores in vitro. T cell crawling on chemokine-coated endothelial cells under shear was severely impaired by ROCK inhibition, whereas transendothelial migration was only reduced through endothelial cells with high, but not low, barrier properties. Using three-dimensional thick-tissue imaging and dynamic two-photon microscopy of T cell motility in lymphoid tissue, we demonstrated a significant role for uropod contractility in intraluminal crawling and transendothelial migration through lymph node, but not bone marrow, endothelial cells. Finally, we demonstrated that ICAM-1, but not anatomical constraints or integrin-independent interactions, reduced parenchymal motility of inhibitor-treated T cells within the dense lymphoid microenvironment, thus assigning context-dependent roles for uropod contraction during lymphocyte recirculation. 相似文献