全文获取类型
收费全文 | 573篇 |
免费 | 51篇 |
国内免费 | 1篇 |
专业分类
625篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 16篇 |
2021年 | 27篇 |
2020年 | 7篇 |
2019年 | 20篇 |
2018年 | 17篇 |
2017年 | 15篇 |
2016年 | 20篇 |
2015年 | 48篇 |
2014年 | 47篇 |
2013年 | 52篇 |
2012年 | 56篇 |
2011年 | 29篇 |
2010年 | 27篇 |
2009年 | 31篇 |
2008年 | 30篇 |
2007年 | 31篇 |
2006年 | 32篇 |
2005年 | 26篇 |
2004年 | 19篇 |
2003年 | 15篇 |
2002年 | 10篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1960年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1947年 | 2篇 |
1946年 | 1篇 |
1937年 | 2篇 |
1934年 | 4篇 |
1933年 | 1篇 |
1931年 | 1篇 |
1929年 | 2篇 |
1928年 | 2篇 |
1926年 | 1篇 |
1925年 | 1篇 |
排序方式: 共有625条查询结果,搜索用时 15 毫秒
1.
2.
Deae-eddine Krim Abdeslem Rrhioua Mustapha Zerfaoui Dikra Bakari Mohammed Hamal Mohamed Moukhlissi 《Reports of Practical Oncology and Radiotherapy》2022,27(5):832
BackgroundMonte Carlo simulation is generally appreciated as an extraordinary technique to investigate particle physics processes and interactions in nuclear medicine and Radiation Therapy. The present task validates a new methodology of Monte Carlo simulation based on the Multithreading technique to reduce CPU time to simulate a 6 MV photon beam provided by the Elekta Synergy MLCi2 platform medical linear accelerator treatment head utilizing TOpas version 3.6 Monte Carlo software and the Slurm Marwan cluster.Materials and methodsThe simulation includes the linear accelerator (LINAC) major components. Calculations are performed for the photon beam with several treatment field sizes varying from 3 × 3 to 10 × 10 cm2 at a 100 cm of distance from the source to the surface of the IBA dosimetry water box. The simulation was wholly approved by comparison with experimental distributions. To evaluate simulation accuracy, gamma index formalism for (2%/2mm) and (3%/2mm) criteria, Distance To Agreement DTA, and the estimator standard error ɛ and ɛmax are used.ResultsGood agreement between simulations and measurements was observed for depth doses and lateral dose profiles, respectively. The gamma index comparisons also highlighted this agreement; more than 97% of the points for all simulations satisfy the quality assurance criteria of (2%/2mm). Regarding calculation performance, the event processing speed is faster using Gate-[mp] compared to TOpas-[mt] mode when running the identical simulation code for both.ConclusionsConsequently, according to the achieved results, the proposed methodology shows the first validation of TOpas in radiotherapy linacs simulations and a reduction in calculation time, capping simulation accuracy as much as possible. For this reason, this software is recommended to be serviceable for Treatment Planning Systems (TPS) purposes. 相似文献
3.
NARC-1/PCSK9 and its natural mutants: zymogen cleavage and effects on the low density lipoprotein (LDL) receptor and LDL cholesterol 总被引:1,自引:0,他引:1
Benjannet S Rhainds D Essalmani R Mayne J Wickham L Jin W Asselin MC Hamelin J Varret M Allard D Trillard M Abifadel M Tebon A Attie AD Rader DJ Boileau C Brissette L Chrétien M Prat A Seidah NG 《The Journal of biological chemistry》2004,279(47):48865-48875
The discovery of autosomal dominant hypercholesterolemic patients with mutations in the PCSK9 gene, encoding the proprotein convertase NARC-1, resulting in the missense mutations suggested a role in low density lipoprotein (LDL) metabolism. We show that the endoplasmic reticulum-localized proNARC-1 to NARC-1 zymogen conversion is Ca2+-independent and that within the zymogen autocatalytic processing site SSVFAQ [downward arrow]SIP Val at P4 and Pro at P3' are critical. The S127R and D374Y mutations result in approximately 50-60% and > or =98% decrease in zymogen processing, respectively. In contrast, the double [D374Y + N157K], F216L, and R218S natural mutants resulted in normal zymogen processing. The cell surface LDL receptor (LDLR) levels are reduced by 35% in lymphoblasts of S127R patients. The LDLR levels are also reduced in stable HepG2 cells overexpressing NARC-1 or its natural mutant S127R, and this reduction is abrogated in the presence of 5 mm ammonium chloride, suggesting that overexpression of NARC-1 increases the turnover rate of the LDLR. Adenoviral expression of wild type human NARC-1 in mice resulted in a maximal approximately 9-fold increase in circulating LDL cholesterol, while in LDLR-/- mice a delayed approximately 2-fold increase in LDL cholesterol was observed. In conclusion, NARC-1 seems to affect both the level of LDLR and that of circulating apoB-containing lipoproteins in an LDLR-dependent and -independent fashion. 相似文献
4.
Nitrate transport in plants: which gene and which control? 总被引:7,自引:0,他引:7
5.
Christos E. Zois Anne M. Hendriks Syed Haider Elisabete Pires Esther Bridges Dimitra Kalamida Dimitrios Voukantsis B. Christoffer Lagerholm Rudolf S. N. Fehrmann Wilfred F. A. den Dunnen Andrei I. Tarasov Otto Baba John Morris Francesca M. Buffa James S. O. McCullagh Mathilde Jalving Adrian L. Harris 《Cell death & disease》2022,13(6)
Channelling of glucose via glycogen, known as the glycogen shunt, may play an important role in the metabolism of brain tumours, especially in hypoxic conditions. We aimed to dissect the role of glycogen degradation in glioblastoma (GBM) response to ionising radiation (IR). Knockdown of the glycogen phosphorylase liver isoform (PYGL), but not the brain isoform (PYGB), decreased clonogenic growth and survival of GBM cell lines and sensitised them to IR doses of 10–12 Gy. Two to five days after IR exposure of PYGL knockdown GBM cells, mitotic catastrophy and a giant multinucleated cell morphology with senescence-like phenotype developed. The basal levels of the lysosomal enzyme alpha-acid glucosidase (GAA), essential for autolysosomal glycogen degradation, and the lipidated forms of gamma-aminobutyric acid receptor-associated protein-like (GABARAPL1 and GABARAPL2) increased in shPYGL U87MG cells, suggesting a compensatory mechanism of glycogen degradation. In response to IR, dysregulation of autophagy was shown by accumulation of the p62 and the lipidated form of GABARAPL1 and GABARAPL2 in shPYGL U87MG cells. IR increased the mitochondrial mass and the colocalisation of mitochondria with lysosomes in shPYGL cells, thereby indicating reduced mitophagy. These changes coincided with increased phosphorylation of AMP-activated protein kinase and acetyl-CoA carboxylase 2, slower ATP generation in response to glucose loading and progressive loss of oxidative phosphorylation. The resulting metabolic deficiencies affected the availability of ATP required for mitosis, resulting in the mitotic catastrophy observed in shPYGL cells following IR. PYGL mRNA and protein levels were higher in human GBM than in normal human brain tissues and high PYGL mRNA expression in GBM correlated with poor patient survival. In conclusion, we show a major new role for glycogen metabolism in GBM cancer. Inhibition of glycogen degradation sensitises GBM cells to high-dose IR indicating that PYGL is a potential novel target for the treatment of GBMs.Subject terms: Cancer metabolism, CNS cancer 相似文献
6.
7.
8.
Mathilde Chaineau Maria S. Ioannou Peter S. McPherson 《Traffic (Copenhagen, Denmark)》2013,14(11):1109-1117
Rabs are the largest family of small GTPases and are master regulators of membrane trafficking. Following activation by guanine‐nucleotide exchange factors (GEFs), each Rab binds a specific set of effector proteins that mediate the various downstream functions of that Rab. Then, with the help of GTPase‐activating proteins, the Rab converts GTP to GDP, terminating its function. There are over 60 Rabs in humans and only a subset has been analyzed in any detail. Recently, Rab35 has emerged as a key regulator of cargo recycling at endosomes, with an additional role in regulation of the actin cytoskeleton. Here, we will focus on the regulation of Rab35 activity by the connecdenn/DENND1 family of GEFs and the TBC1D10/EPI64 family of GTPase‐activating proteins. We will describe how analysis of these proteins, as well as a plethora of Rab35 effectors has provided insights into Rab35 function. Finally, we will describe how Rab35 provides a novel link between the Rab and Arf family of GTPases with implications for tumor formation and invasiveness . 相似文献
9.
10.