全文获取类型
收费全文 | 344篇 |
免费 | 11篇 |
国内免费 | 24篇 |
专业分类
丛书文集 | 10篇 |
教育与普及 | 5篇 |
理论与方法论 | 1篇 |
现状及发展 | 114篇 |
研究方法 | 1篇 |
综合类 | 248篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 7篇 |
2011年 | 16篇 |
2010年 | 5篇 |
2009年 | 20篇 |
2008年 | 19篇 |
2007年 | 25篇 |
2006年 | 28篇 |
2005年 | 26篇 |
2004年 | 24篇 |
2003年 | 31篇 |
2002年 | 14篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 11篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 2篇 |
排序方式: 共有379条查询结果,搜索用时 443 毫秒
281.
步宇翔 《山东大学学报(理学版)》2011,46(10):152-159
本文综述了生物体内电荷跳跃转移的一些新特征。重点阐述了蛋白质电荷转移过程中一种可能的中间体--溶剂化电子--的结构性质特征以及在蛋白质长程电荷转移中的重要作用。蛋白质中存在着诸多基团、分子片或电正性区域,比如:质子化的碱性支链基团、芳香环、极性肽链、螺旋及结构水簇等,它们可以俘获电子、然后释放,扮演着电子跳跃转移中继站的作用。这种基于溶剂化电子的电子跳跃转移模式构成了蛋白质内电子长程转移的新途径。 相似文献
282.
兔抗Red蛋白抗血清的纯化及MC3T3细胞中Red蛋白表达时相的分析 总被引:1,自引:0,他引:1
为了纯化兔抗Red蛋白的3种多克隆抗体,并用其研究Red蛋白在真核细胞中的表达时相,首先于30℃培养了不含H的基因的空载体(pDH2)大肠菌,经彻底裂菌后用丙酮沉淀仝菌蛋白,用其在不同时间吸附3种待纯化的Red抗体,然后用间接ELISA法及Western-blot法检测r3种抗体的效价和特异性。最后州纯化后的3种Red抗体检测三顺反子表达载体pCMV-glblx的3种蛋白表达产物在MC3T3细胞中的表达时相。EUSA及Western-blot检测结果表明:3种抗血清经纯化后特异性好且效价没有受到影响,随后用纯化的抗体成功地研究了Red基因在真核细胞中的表达时相,此结果为Red重组系统在真核生物基因功能的研究中提供了必要的条件。 相似文献
283.
Protein-O-mannosyltransferases (Pmt proteins) catalyse the addition of mannose to serine or threonine residues of secretory proteins.
This modification was described first for yeast and later for other fungi, mammals, insects and recently also for bacteria.
O-mannosylation depends on specific isoforms of the three Pmt1, 2 and 4 subfamilies. In fungi, O-mannosylation determines the structure and integrity of cell walls, as well as cellular differentiation and virulence. O-mannosylation of specific secretory proteins of the human fungal pathogen Candida albicans and of the bacterial pathogen Mycobacterium tuberculosis contributes significantly to virulence. In mammals and insects, Pmt proteins are essential for cellular differentiation and
development, while lack of Pmt activity causes Walker-Warburg syndrome (muscular dystrophy) in humans. The susceptibility
of human cells to certain viruses may also depend on O-mannosyl chains. This review focuses on the various roles of Pmt proteins in cellular differentiation, development and virulence.
Received 6 September 2007; received after revision 3 October 2007; accepted 5 October 2007 相似文献
284.
Defining a neuron: neuronal ELAV proteins 总被引:1,自引:1,他引:0
Neuronal cells strongly depend on the control exerted by RNA-binding proteins (RBPs) on gene expression for the establishment
and maintenance of their phenotype. Neuronal ELAV (nELAV) proteins are RBPs able to influence virtually every aspect of the
postsynthesis fate of bound mRNAs, from polyadenylation, alternative splicing and nuclear export to cytoplasmic localization,
stability and translation. They enhance gene expression through the last two, best documented activities, increasing mRNA
half-life and promoting protein synthesis by a still-unknown molecular mechanism. Developmentally, nELAV proteins have been
shown to act as inducers of the transition between neural stem/progenitor cells and differentiation-committed cells, also
assisting these neuroblasts in the completion of their maturation program. In brain physiology, they are also the first RBPs
demonstrated to have a pivotal role in memory, where they probably control mRNA availability for translation in subcellular
domains, thereby providing a biochemical means for selective increase in synaptic strength.
Received 15 January 2007; received after revision 10 August 2007; accepted 6 September 2007 相似文献
285.
Diverse molecular functions of Hu proteins 总被引:1,自引:1,他引:0
286.
287.
F. Magherini A. Carpentieri A. Amoresano T. Gamberi C. De Filippo L. Rizzetto M. Biagini P. Pucci A. Modesti 《Cellular and molecular life sciences : CMLS》2009,66(5):933-947
In this study, a proteomic approach that combines selective labelling of proteins containing reduced cysteine residues with
two-dimensional electrophoresis/mass spectrometry was used to evaluate the redox state of protein cysteines during chronological
ageing in Saccharomyces cerevisiae. The procedure was developed on the grounds that biotinconjugated iodoacetamide (BIAM) specifically reacts with reduced cysteine
residues. BIAM-labelled proteins can then be selectively isolated by streptavidin affinity capture. We compared cells grown
on 2% glucose in the exponential phase and during chronological ageing and we found that many proteins undergo cysteine oxidation.
The target proteins include enzymes involved in glucose metabolism. Both caloric restriction and growth on glycerol resulted
in a decrease in the oxidative modification. Furthermore, in these conditions a reduced production of ROS and a more negative
glutathione half cell redox potential were observed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Received 15 September 2008; received after revision 17 December 2008; accepted 06 January 2009 相似文献
288.
289.
在酸性溶液中,比布列西猩红与蛋白质作用,产生共振光散射(RLS)增强光谱,最大散射峰位于286.0nm,且增强RLS强度在一定范围内与蛋白质浓度呈线性关系.研究了pH、比布列西猩红的浓度及离子强度对RLS强度的影响.人血清白蛋白(HSA)的线性范围为0.02~4.0μg/mL,牛血清白蛋(BSA)0.02-4.5μg/mL,溶菌酶(Lys)为0.02-2.0μg/mL,γ-球蛋白(γ-IgG)为0.0l-7.5μg/mL.测定的检测限(3σ)分别为:16.6ng/mL(HSA),15.7ng/mL(BSA),16.7ng/mL(Lys)和7.5ng/mL(γ-IgG).此方法用于人血清样品测定,结果满意. 相似文献
290.
通过催化抑制性G蛋白α亚基(Gαi/o)的ADP核糖基化,百日咳毒素(PTX)使Gαi/o不能活化,继而抑制Gαi/o-腺苷酸环化酶(AC)-cAMP-蛋白激酶A(PKA)-L型电压门控钙(Ca(L)2 )通道.Ca(L)2 通道可能是拟除虫菊酯类杀虫剂的靶标.本实验观察了PTX对三氟氯氰菊酯(Cy)抗性及敏感棉铃虫神经细胞Ca(L)2 通道的影响, 以期从Ca(L)2 通道动力学的角度探讨棉铃虫对拟除虫菊酯类杀虫剂产生抗性的机制.急性分离并经12-16 h无菌培养3-4龄棉铃虫神经细胞.实验分4组:①Cy敏感组(Cy-S组);②Cy抗性组(Cy-R组);③Cy-S-PTX组; ④Cy-R-PTX组.400 ng/mL PTX加入培养基中.采用全细胞膜片钳技术记录各组,ICa(L).结果显示:(1)各组 Ca(L)2 通道的激活电压均是-35--30 mV,最大激活电压是0 mV,但Cy-S-PTX组的最大激活电压是 -10 mV;(2)分别与Cy-S组和Cy-R-PTX组峰值电流密度相比,Cy-S-PTX组峰值电流密度分别增高52.06 %和44.81%(P<0.01),提示Cy-S-PTX组Ca(L)2 通道电导可能增大.Cy-S组和Cy-R组间的峰值电流密度无统计学差异;(3)与Cy-S组相比,Cy-S-PTX组神经细胞Ca(L)2 通道的半数激活电压向超极化方向移动5.1 mV (P<0.05),半数失活电压向超极化方向移动5.93 mV(P<0.05),提示PTX使敏感组神经细胞的Ca(L)2 通道更容易激活和失活;(4)与Cy-R组相比,Cy-R-PTX神经细胞Ca(L)2 通道的半数激活电压几乎未变,半数失活电压向去极化方向移动2.42 mV(P>0.05),提示PTX对抗性组神经细胞的影响不明显;(5)Cy-R组与Cy-S组神经细胞Ca(L)2 通道的半数激活电压和半数失活电压无显著性差异.结果提示:(1)棉铃虫神经细胞存在(Gαi/o)-AC- cAMP-PKA-Ca(L)2 通道信号传导途径;(2)PTX敏感的抑制性Gi/o蛋白的基础活性对棉铃虫神经细胞Ca(L)2 通道有影响;(3)PTX对敏感虫神经细胞的Ca(L)2 通道的影响较对抗性棉铃虫神经细胞Ca(L)2 通道的影响明显,提示抗性棉铃虫对拟除虫菊酯类杀虫剂产生抗性的机理可能与其Ca(L)2 通道对Gαi/o-AC-cAMP-PKA-Ca(L)2 通道调控不敏感有关. 相似文献