全文获取类型
收费全文 | 786篇 |
免费 | 76篇 |
出版年
2023年 | 7篇 |
2022年 | 19篇 |
2021年 | 23篇 |
2020年 | 12篇 |
2019年 | 7篇 |
2018年 | 23篇 |
2017年 | 15篇 |
2016年 | 31篇 |
2015年 | 56篇 |
2014年 | 67篇 |
2013年 | 69篇 |
2012年 | 83篇 |
2011年 | 71篇 |
2010年 | 48篇 |
2009年 | 36篇 |
2008年 | 50篇 |
2007年 | 50篇 |
2006年 | 41篇 |
2005年 | 39篇 |
2004年 | 27篇 |
2003年 | 30篇 |
2002年 | 19篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有862条查询结果,搜索用时 15 毫秒
131.
Metalloprotease meprin beta generates nontoxic N-terminal amyloid precursor protein fragments in vivo 总被引:1,自引:0,他引:1
Jefferson T Čaušević M auf dem Keller U Schilling O Isbert S Geyer R Maier W Tschickardt S Jumpertz T Weggen S Bond JS Overall CM Pietrzik CU Becker-Pauly C 《The Journal of biological chemistry》2011,286(31):27741-27750
Identification of physiologically relevant substrates is still the most challenging part in protease research for understanding the biological activity of these enzymes. The zinc-dependent metalloprotease meprin β is known to be expressed in many tissues with functions in health and disease. Here, we demonstrate unique interactions between meprin β and the amyloid precursor protein (APP). Although APP is intensively studied as a ubiquitously expressed cell surface protein, which is involved in Alzheimer disease, its precise physiological role and relevance remain elusive. Based on a novel proteomics technique termed terminal amine isotopic labeling of substrates (TAILS), APP was identified as a substrate for meprin β. Processing of APP by meprin β was subsequently validated using in vitro and in vivo approaches. N-terminal APP fragments of about 11 and 20 kDa were found in human and mouse brain lysates but not in meprin β(-/-) mouse brain lysates. Although these APP fragments were in the range of those responsible for caspase-induced neurodegeneration, we did not detect cytotoxicity to primary neurons treated by these fragments. Our data demonstrate that meprin β is a physiologically relevant enzyme in APP processing. 相似文献
132.
133.
Katja Seider Franziska Gerwien Lydia Kasper Stefanie Allert Sascha Brunke Nadja Jablonowski Tobias Schwarzmüller Dagmar Barz Steffen Rupp Karl Kuchler Bernhard Hube 《Eukaryotic cell》2014,13(1):170-183
Candida glabrata is both a human fungal commensal and an opportunistic pathogen which can withstand activities of the immune system. For example, C. glabrata can survive phagocytosis and replicates within macrophages. However, the mechanisms underlying intracellular survival remain unclear. In this work, we used a functional genomic approach to identify C. glabrata determinants necessary for survival within human monocyte-derived macrophages by screening a set of 433 deletion mutants. We identified 23 genes which are required to resist killing by macrophages. Based on homologies to Saccharomyces cerevisiae orthologs, these genes are putatively involved in cell wall biosynthesis, calcium homeostasis, nutritional and stress response, protein glycosylation, or iron homeostasis. Mutants were further characterized using a series of in vitro assays to elucidate the genes'' functions in survival. We investigated different parameters of C. glabrata-phagocyte interactions: uptake by macrophages, replication within macrophages, phagosomal pH, and recognition of mutant cells by macrophages as indicated by production of reactive oxygen species and tumor necrosis factor alpha (TNF-α). We further studied the cell surface integrity of mutant cells, their ability to grow under nutrient-limited conditions, and their susceptibility to stress conditions mirroring the harsh environment inside a phagosome. Additionally, resistance to killing by neutrophils was analyzed. Our data support the view that immune evasion is a key aspect of C. glabrata virulence and that increased immune recognition causes increased antifungal activities by macrophages. Furthermore, stress resistance and efficient nutrient acquisition, in particular, iron uptake, are crucial for intraphagosomal survival of C. glabrata. 相似文献
134.
Tobias Schwarzmüller Biao Ma Ekkehard Hiller Fabian Istel Michael Tscherner Sascha Brunke Lauren Ames Arnaud Firon Brian Green Vitor Cabral Marina Marcet-Houben Ilse D. Jacobsen Jessica Quintin Katja Seider Ingrid Frohner Walter Glaser Helmut Jungwirth Sophie Bachellier-Bassi Murielle Chauvel Ute Zeidler Dominique Ferrandon Toni Gabaldón Bernhard Hube Christophe d'Enfert Steffen Rupp Brendan Cormack Ken Haynes Karl Kuchler 《PLoS pathogens》2014,10(6)
The opportunistic fungal pathogen Candida glabrata is a frequent cause of candidiasis, causing infections ranging from superficial to life-threatening disseminated disease. The inherent tolerance of C. glabrata to azole drugs makes this pathogen a serious clinical threat. To identify novel genes implicated in antifungal drug tolerance, we have constructed a large-scale C. glabrata deletion library consisting of 619 unique, individually bar-coded mutant strains, each lacking one specific gene, all together representing almost 12% of the genome. Functional analysis of this library in a series of phenotypic and fitness assays identified numerous genes required for growth of C. glabrata under normal or specific stress conditions, as well as a number of novel genes involved in tolerance to clinically important antifungal drugs such as azoles and echinocandins. We identified 38 deletion strains displaying strongly increased susceptibility to caspofungin, 28 of which encoding proteins that have not previously been linked to echinocandin tolerance. Our results demonstrate the potential of the C. glabrata mutant collection as a valuable resource in functional genomics studies of this important fungal pathogen of humans, and to facilitate the identification of putative novel antifungal drug target and virulence genes. 相似文献
135.
Christian Ude Michael Findeis Gernot T. John Thomas Scheper Sascha Beutel 《Engineering in Life Science》2014,14(5):467-476
A novel online sensor system for noninvasive and continuous monitoring of cell growth in shake flasks is described. The measurement principle is based on turbidity measurement by detecting 180°‐scattered light and correlation to OD by nonlinear calibration models. The sensor system was integrated into a commercial shaking tablar to read out turbidity from below the shake flasks bottom. The system was evaluated with two model microorganisms, Escherichia coli K12 as prokaryotic and Saccharomyces cerevisiae as eukaryotic model. The sensor allowed an accurate monitoring of turbidity and correlation with OD600 ≤ 30. The determination of online OD showed relative errors of about 7.5% for E. coli K12 and 12% for S. cerevisiae. This matches the errors of the laborious offline OD and thus facilitates to overcome the drawbacks of the classical method as risk of contamination and decreasing volumes through sampling. One major challenge was to ensure a defined, nonvarying measurement zone as the rotating suspension in the shake flask forms a liquid sickle which circulates round the flasks inner bottom wall. The resulting alteration of liquid height above the sensor could be compensated by integration of an acceleration sensor into the tablar to synchronize the sensor triggering. 相似文献
136.
Thaddaeus Pfaffenwimmer Wolfgang Reiter Thorsten Brach Veronika Nogellova Daniel Papinski Martina Schuschnig Christine Abert Gustav Ammerer Sascha Martens Claudine Kraft 《EMBO reports》2014,15(8):862-870
Autophagy is the major pathway for the delivery of cytoplasmic material to the vacuole or lysosome. Selective autophagy is mediated by cargo receptors, which link the cargo to the scaffold protein Atg11 and to Atg8 family proteins on the forming autophagosomal membrane. We show that the essential kinase Hrr25 activates the cargo receptor Atg19 by phosphorylation, which is required to link cargo to the Atg11 scaffold, allowing selective autophagy to proceed. We also find that the Atg34 cargo receptor is regulated in a similar manner, suggesting a conserved mechanism. 相似文献
137.
Jelena Kornej Borislav Dinov Andrew D. Blann Sascha Rolf Arash Arya Josephine Schmidl Daniela Husser Gerhard Hindricks Andreas Bollmann Gregory Y. H. Lip 《PloS one》2014,9(11)
Background
Catheter ablation (CA) of atrial fibrillation (AF) is associated with inflammatory response, endothelial damage and with increased risk of thrombosis. However, whether these processes differ in peripheral and cardiac circulation is unknown.Methods
Plasma markers (von Willebrand factor (vWf), soluble P-selectin (sPsel) and interleukin-6 (IL-6)) were measured by ELISA at three time points in 80 patients (62±10 years, 63% males, 41% paroxysmal AF) undergoing CA. These were at baseline – from femoral vein (FV) and left atrium (LA) before ablation; directly after ablation – from the pulmonary vein (PV), LA and FV; and 24 hours after procedure – from a cubital vein (CV).Results
The levels of vWF and IL6 – but not sP-sel – increased significantly 24h after procedure (p<0.001). Baseline vWF was significantly associated with persistent AF (Beta = .303, p = 0.006 and Beta = .300, p = 0.006 for peripheral and cardiac levels, respectively), while persistent AF (Beta = .250, p = 0.031) and LAA flow pattern (Beta = .386, p<0.001) remained associated with vWF in cardiac blood after ablation. Advanced age was significantly associated with IL6 levels at baseline and after ablation in peripheral and cardiac blood. There were no clinical, procedural or anti-coagulation characteristics associated with sP-sel levels in cardiac blood, while peripheral sP-sel levels were associated with hypertension before (Beta = −.307, p = 0.007) and with persistent AF after ablation (Beta = −.262, p = 0.020).Conclusions
vWF levels are higher in persistent AF and are associated with LAA rheological pattern after AF ablation. Increase of peripheral vWF and IL6 levels after procedure supports current AF ablation management with careful control of post-procedural anticoagulation to avoid ablation-related thromboembolism. 相似文献138.
Stefan N Martin-Killias P Wyss-Stoeckle S Honegger A Zangemeister-Wittke U Plückthun A 《Journal of molecular biology》2011,413(4):826-843
Designed Ankyrin Repeat Proteins (DARPins) represent a novel class of binding molecules. Their favorable biophysical properties such as high affinity, stability and expression yields make them ideal candidates for tumor targeting. Here, we describe the selection of DARPins specific for the tumor-associated antigen epithelial cell adhesion molecule (EpCAM), an approved therapeutic target on solid tumors. We selected DARPins from combinatorial libraries by both phage display and ribosome display and compared their binding on tumor cells. By further rounds of random mutagenesis and ribosome display selection, binders with picomolar affinity were obtained that were entirely monomeric and could be expressed at high yields in the cytoplasm of Escherichia coli. One of the binders, denoted Ec1, bound to EpCAM with picomolar affinity (Kd = 68 pM), and another selected DARPin (Ac2) recognized a different epitope on EpCAM. Through the use of a variety of bivalent and tetravalent arrangements with these DARPins, the off-rate on cells was further improved by up to 47-fold. All EpCAM-specific DARPins were efficiently internalized by receptor-mediated endocytosis, which is essential for intracellular delivery of anticancer agents to tumor cells. Thus, using EpCAM as a target, we provide evidence that DARPins can be conveniently selected and rationally engineered to high-affinity binders of various formats for tumor targeting. 相似文献
139.
140.
Wagner S Kufleitner J Zensi A Dadparvar M Wien S Bungert J Vogel T Worek F Kreuter J von Briesen H 《PloS one》2010,5(12):e14213