全文获取类型
收费全文 | 311篇 |
免费 | 38篇 |
国内免费 | 1篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 18篇 |
2015年 | 22篇 |
2014年 | 26篇 |
2013年 | 29篇 |
2012年 | 26篇 |
2011年 | 13篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 11篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 14篇 |
2004年 | 14篇 |
2003年 | 2篇 |
2002年 | 6篇 |
2001年 | 11篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1994年 | 2篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有350条查询结果,搜索用时 703 毫秒
341.
Tecalco–Cruz Angeles C. Pedraza-Chaverri José Briones-Herrera Alfredo Cruz-Ramos Eduardo López–Canovas Lilia Zepeda–Cervantes Jesús 《Molecular and cellular biochemistry》2022,477(3):915-925
Molecular and Cellular Biochemistry - Alzheimer’s disease (AD) is the most common type of dementia associated with age-related neurodegeneration. Alteration of several molecular mechanisms... 相似文献
342.
343.
Moshe Giladi Lirin Michaeli Lior Almagor Dana Bar-On Tal Buki Uri Ashery Daniel Khananshvili Joel A. Hirsch 《Journal of molecular biology》2013
DOC2B (double-C2 domain) protein is thought to be a high-affinity Ca2 + sensor for spontaneous and asynchronous neurotransmitter release. To elucidate the molecular features underlying its physiological role, we determined the crystal structures of its isolated C2A and C2B domains and examined their Ca2 +-binding properties. We further characterized the solution structure of the tandem domains (C2AB) using small-angle X-ray scattering. In parallel, we tested structure–function correlates with live cell imaging tools. We found that, despite striking structural similarity, C2B binds Ca2 + with considerably higher affinity than C2A. The C2AB solution structure is best modeled as two domains with a highly flexible orientation and no difference in the presence or absence of Ca2 +. In addition, kinetic studies of C2AB demonstrate that, in the presence of unilamellar vesicles, Ca2 + binding is stabilized, as reflected by the ~ 10-fold slower rate of Ca2 + dissociation than in the absence of vesicles. In cells, isolated C2B translocates to the plasma membrane (PM) with an EC50 of 400 nM while the C2A does not translocate at submicromolar Ca2 + concentrations, supporting the biochemical observations. Nevertheless, C2AB translocates to the PM with an ~ 2-fold lower EC50 and to a greater extent than C2B. Our results, together with previous studies, reveal that the C2B is the primary Ca2 + sensing unit in DOC2B, whereas C2A enhances the interaction of C2AB with the PM. 相似文献
345.
Hernández–Montañez Zahuiti López–Ramírez María Patricia Delgado–Balbuena Laura Dendooven Luc Bello–López Juan Manuel 《Annals of microbiology》2015,65(2):827-831
Both biotic and abiotic characteristics of an ecosystem play an important role in the horizontal transfer of DNA in nature. The abiotic factor temperature has a great impact on such transfers as it controls the metabolic activity of mesophilic microorganisms. Moreover, psychrophilic bacteria, which are not affected by low temperatures, are considered to be potential donors of DNA to mesophilic bacteria under temperature stress conditions. In our study, mesophilic Aeromonas spp. strains isolated from fresh fish were genotypically identified and used as recipients in in vitro conjugal transfer experiments using plasmid pRAS1 from psychrophilic strain Aeromonas salmonicida 718 at three different temperatures (8, 15 and 20 °C). The transfer of the plasmid was confirmed by identifying the elements of the integron in pRAS1. A low temperatures did not prevent the transfer of the pRAS1 plasmid to Aeromonas veronii, A. media, A. hydrophila and A. caviae strains, which showed detectable conjugation frequencies of 10–8 at 8 °C. In other strains of the same species, transconjugants were not detected, which indicated that the genetic background of each strain directly affected the ability to be a recipient of this plasmid at the temperatures tested. Our results demonstrate that mesophilic Aeromonas spp. strains are potential reservoirs of extrachromosomal genetic material. Implications of this plasmid transfer at low temperatures and its possible consequences for human health are discussed. 相似文献
346.
Raquel Campos–Herrera Mary Barbercheck Casey W. Hoy S. Patricia Stock 《Journal of nematology》2012,44(2):162-176
Entomopathogenic nematodes (EPNs) in the families Heterorhabditidae and Steinernematidae have a mutualistic–symbiotic association with enteric γ-Proteobacteria (Steinernema–Xenorhabdus and Heterorhabditis–Photorhabdus), which confer high virulence against insects. EPNs have been studied intensively because of their role as a natural mortality factor for soil-dwelling arthropods and their potential as biological control agents for belowground insect pests. For many decades, research on EPNs focused on the taxonomy, phylogeny, biogeography, genetics, physiology, biochemistry and ecology, as well as commercial production and application technologies. More recently, EPNs and their bacterial symbionts are being viewed as a model system for advancing research in other disciplines such as soil ecology, symbiosis and evolutionary biology. Integration of existing information, particularly the accumulating information on their biology, into increasingly detailed population models is critical to improving our ability to exploit and manage EPNs as a biological control agent and to understand ecological processes in a changing world. Here, we summarize some recent advances in phylogeny, systematics, biogeography, community ecology and population dynamics models of EPNs, and describe how this research is advancing frontiers in ecology. 相似文献
347.
Ghadeer M. Albadrani Mona N. BinMowyna May N. Bin-Jumah Gehan El–Akabawy Hussain Aldera Ammar M. AL-Farga 《Saudi Journal of Biological Sciences》2021,28(5):2772-2782
This study investigated the anti-remodeling and anti-fibrotic and effect of quercetin (QUR) in the remote non-infarcted of rats after myocardial infarction (MI). Rats were divided as control, control + QUR, MI, and MI + QUR. MI was introduced to the rats by ligating the eft anterior descending (LAD) coronary artery. All treatments were given for 30 days, daily. QUR persevered the LV hemodynamic parameters and prevented remote myocardium damage and fibrosis. Also, QUR supressed the generation of ROS, increased the nuclear levels of Nrf2, and enhanced SOD and GSH levels in the LVs of the control and MI model rats. It also reduced angiotensin II, nuclear level/activity of the nuclear factor NF-κβ p65, and protein expression of TGF-β1, α-SMA, and total/phospho-smad3 in the LVs of both groups. Concomitantly, QUR upregulated LV smad7 and BMP7. In conclusion, QUR prevents MI-induced LV remodeling by antioxidant, anti-inflammatory, and anti-fibroticα effects mediated by ROS scavenging, suppressing NF-κβ, and stimulating Nrf-2, Smad7, and BMP7. 相似文献
348.
Delta pH and membrane potential in bacterial chromatophores 总被引:7,自引:0,他引:7
349.
350.
Etana Padan 《BBA》2014
The crystal structure of down-regulated NhaA crystallized at acidic pH 4 [21] has provided the first structural insights into the antiport mechanism and pH regulation of a Na+/H+ antiporter [22]. On the basis of the NhaA crystal structure [21] and experimental data (reviewed in [2,22,38] we have suggested that NhaA is organized into two functional regions: (i) a cluster of amino acids responsible for pH regulation (ii) a catalytic region at the middle of the TM IV/XI assembly, with its unique antiparallel unfolded regions that cross each other forming a delicate electrostatic balance in the middle of the membrane. This unique structure contributes to the cation binding site and allows the rapid conformational changes expected for NhaA. Extended chains interrupting helices appear now a common feature for ion binding in transporters. However the NhaA fold is unique and shared by ASBTNM [30] and NapA [29]. Computation [13], electrophysiology [69] combined with biochemistry [33,47] have provided intriguing models for the mechanism of NhaA. However, the conformational changes and the residues involved have not yet been fully identified. Another issue which is still enigma is how energy is transduced “in this ‘nano-machine.’” We expect that an integrative approach will reveal the residues that are crucial for NhaA activity and regulation, as well as elucidate the pHand ligand-induced conformational changes and their dynamics. Ultimately, integrative results will shed light on the mechanism of activity and pH regulation of NhaA, a prototype of the CPA2 family of transporters. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference. 相似文献