首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   252篇
  完全免费   10篇
  2019年   3篇
  2018年   3篇
  2017年   1篇
  2016年   3篇
  2015年   7篇
  2014年   8篇
  2013年   11篇
  2012年   6篇
  2011年   7篇
  2010年   3篇
  2009年   9篇
  2008年   12篇
  2007年   11篇
  2006年   12篇
  2005年   6篇
  2004年   11篇
  2003年   9篇
  2002年   9篇
  2001年   5篇
  2000年   9篇
  1999年   15篇
  1998年   7篇
  1997年   11篇
  1996年   9篇
  1995年   15篇
  1994年   11篇
  1993年   8篇
  1992年   8篇
  1991年   6篇
  1990年   3篇
  1989年   2篇
  1988年   6篇
  1987年   3篇
  1986年   2篇
  1985年   3篇
  1984年   1篇
  1983年   2篇
  1981年   1篇
  1979年   2篇
  1978年   1篇
  1975年   1篇
排序方式: 共有262条查询结果,搜索用时 31 毫秒
1.
Calreticulin: not just another calcium-binding protein   总被引:15,自引:0,他引:15  
In this paper we review some of the rapidly expanding information about calreticulin, a Ca2+-binding/storage protein of the endoplasmic reticulum. The emphasis is placed on the structure and function of calreticulin. We believe that calreticulin is a multifunctional Ca2+-binding protein and that distinct functional properties of the protein may be localized to each of the three structural domains of calreticulin. Most evidence indicates that calreticulin is a resident endoplasmic reticulum protein. However, it can also be found outside of the endoplasmic reticulum compartment, i.e. in the nuclear envelope, in the nucleus, in the cytotoxic granules in T-lymphocytes and in acrosomal vesicles of sperm cells. The evidence reviewed here clearly suggests that calreticulin has other functions in addition to its role as a Ca2+ storage protein in the endoplasmic reticulum.Abbreviations SR sarcoplasmic reticulum - ER endoplasmic reticulum  相似文献
2.
To reach fertilization competence, sperm undergo an incompletely understood series of morphological and molecular maturational processes, termed capacitation, involving, among other processes, protein tyrosine phosphorylation and increased intracellular calcium. Hyperactivated motility and an ability to undergo the acrosome reaction serve as physiological end points to assess successful capacitation. We report here that acidic (pI 4.0) 86-kDa isoforms of a novel, polymorphic, testis-specific protein, designated calcium-binding tyrosine phosphorylation-regulated protein (CABYR), were tyrosine phosphorylated during in vitro capacitation and bound (45)Ca on 2D gels. Acidic 86-kDa calcium-binding forms of CABYR increased during in vitro capacitation, and calcium binding to these acidic forms was abolished by dephosphorylation with alkaline phosphatase. Six variants of CABYR containing two coding regions (CR-A and CR-B) were cloned from human testis cDNA libraries, including five variants with alternative splice deletions. A motif homologous to the RII dimerization domain of PK-A was present in the N-terminus of CR-A in four CABYR variants. A single putative EF handlike motif was noted in CR-A at aas 197-209, while seven potential tyrosine phosphorylation-like sites were noted in CR-A and four in CR-B. Pro-X-X-Pro (PXXP) modules were identified in the N- and C-termini of CR-A and CR-B. CABYR localizes to the principal piece of the human sperm flagellum in association with the fibrous sheath and is the first demonstration of a sperm protein that gains calcium-binding capacity when phosphorylated during capacitation.  相似文献
3.
Caleosins: Ca2+-binding proteins associated with lipid bodies   总被引:7,自引:0,他引:7  
We have previously identified a rice gene encoding a 27 kDa protein with a single Ca2+-binding EF-hand and a putative membrane anchor. We report here similar genes termed caleosins, CLO, in other plants and fungi; they comprise a multigene family of at least five members in Arabidopsis (AtClo1–5). Northern hybridization demonstrated that AtClo2–4 mRNAs levels were low in various tissues, while AtClo1 mRNA levels were high in developing embryos and mature seeds. Analysis of transgenic Arabidopsis plants expressing the GUS reporter under control of the AtClo1 promoter showed strong levels of expression in developing embryos and also in root tip cells. Antibodies raised against AtCLO1 were used to detect caleosin in cellular fractions of Arabidopsis and rapeseed. This indicated that caleosins are a novel class of lipid body proteins, which may also be associated with an ER subdomain.  相似文献
4.
Competitive Calcium Binding: Implications for Dendritic Calcium Signaling   总被引:6,自引:0,他引:6  
Action potentials evoke calcium transients in dendrites of neocortical pyramidal neurons with time constants of <100 ms at physiological temperature. This time period may not be sufficient for inflowing calcium ions to equilibrate with all present Ca2+-binding molecules. We therefore explored nonequilibrium dynamics of Ca2+ binding to numerous Ca2+ reaction partners within a dendritelike compartment using numerical simulations. After a brief Ca2+ influx, the reaction partner with the fastest Ca2+ binding kinetics initially binds more Ca2+ than predicted from chemical equilibrium, while companion reaction partners bind less. This difference is consolidated and may result in bypassing of slow reaction partners if a Ca2+ clearance mechanism is active. On the other hand, slower reaction partners effectively bind Ca2+ during repetitive calcium current pulses or during slower Ca2+ influx. Nonequilibrium Ca2+ distribution can further be enhanced through strategic placement of the reaction partners within the compartment. Using the Ca2+ buffer EGTA as a competitor of fluo-3, we demonstrate competitive Ca2+ binding within dendrites experimentally. Nonequilibrium calcium dynamics is proposed as a potential mechanism for differential and conditional activation of intradendritic targets.  相似文献
5.
To understand better the mechanisms involved in the transduction of a calcium signal into an intracellular response via multiple calcium-modulated proteins, we have examined the calcium-modulated proteins, S100 and calmodulin, and their intracellular targets in rat C6 glioma cells. Subconfluent, confluent, and postconfluent C6 cells contain predominantly, if not exclusively, the S100 beta polypeptide. The level of S100 beta in C6 cells increases approximately 20-fold from subconfluency to postconfluency whereas the level of calmodulin increases only about two-fold. The subcellular distribution of S100 beta and calmodulin in mitotic cells is similar. However, the subcellular distribution of these proteins in interphase cells is different and appears to change with cell density. Gel overlay analysis demonstrated that the S100- and calmodulin-binding protein profiles are significantly different and that some of the binding proteins appear to change in intensity with cell density. These data demonstrate that S100 beta is the predominant S100 polypeptide in C6 cells and suggest that changes in S100 beta and S100 beta-binding proteins may be involved in regulating S100-mediated intracellular processes in C6 cells. Our studies also suggest that the levels of S100 and calmodulin may be differentially regulated in C6 cells.  相似文献
6.
Ca2+-Binding S100 Proteins in the Central Nervous System   总被引:5,自引:0,他引:5  
A number of neurodegenerative disorders have been attributed to abberrations of intracellular Ca2+ homeostasis regulated by Ca2+-binding proteins. This chapter will focus on the S100B and S100A6 proteins, which are highly expressed in the central nervous system. Their protein structures, localizations, and association with brain pathology as well as their potential use in clinical diagnostics will be discussed.  相似文献
7.
Immunohistochemical techniques were used to examine the presence and co-localisation of a range of putative neurotransmitters and other neuronal markers in the myenteric plexus of the small and large intestine of the mouse. Distinct sub-populations of myenteric neurons were identified, based on the combinations of substances they contained and the distribution of their fibres. In the small intestine, there were two major classes of circular muscle motor neurons; one class was characterised by the presence of nitric oxide synthase, vasoactive intestinal peptide plus neuropeptide Y (NOS/VIP/NPY), and the second class contained calretinin plus substance P (CalR/SP). There were seven classes of neurons that innervated myenteric ganglia; these contained NOS, VIP, NOS/VIP, NPY, CalR/calbindin (CalB), SP or 5-HT. In the large intestine, there were five major classes of motor neurons that contained NOS, NOS/VIP, GABA, SP, or CalR/SP, and seven major classes of neurons that innervated myenteric ganglia and contained NOS, VIP, CalR/CalB, CalR, SP, GABA or 5-HT. Although some aspects of the patterns of co-localisation are similar to those in other species, this study re-inforces recent analyses that indicate significant species differences in neurochemical patterns in the enteric neurons of different species. Received: 28 August 1995 / Accepted: 30 November 1995  相似文献
8.
9.
10.
Summary Specific antibodies raised against a human 28 000 dalton cerebellar calcium-binding protein (CaBP) were used in an immunocytochemical study during development of the rat cerebellum. Both light and electron microscopy showed (1) that labelling was entirely restricted to the Purkinje cells, (2) that it appeared very early in Purkinje cell development, (3) that the entire cell was labelled from the tip of the smallest dendrites to the axonal terminals, and (4) that with increasing age, the immunoreaction appeared to be progressively restricted to the cell and organelle membranes.  相似文献
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号