全文获取类型
收费全文 | 402篇 |
免费 | 27篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 147篇 |
金属工艺 | 1篇 |
机械仪表 | 5篇 |
建筑科学 | 14篇 |
矿业工程 | 1篇 |
能源动力 | 12篇 |
轻工业 | 48篇 |
水利工程 | 8篇 |
石油天然气 | 1篇 |
无线电 | 15篇 |
一般工业技术 | 78篇 |
冶金工业 | 52篇 |
原子能技术 | 1篇 |
自动化技术 | 38篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 20篇 |
2021年 | 22篇 |
2020年 | 15篇 |
2019年 | 9篇 |
2018年 | 21篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 9篇 |
2014年 | 14篇 |
2013年 | 18篇 |
2012年 | 26篇 |
2011年 | 24篇 |
2010年 | 22篇 |
2009年 | 24篇 |
2008年 | 24篇 |
2007年 | 19篇 |
2006年 | 17篇 |
2005年 | 14篇 |
2004年 | 12篇 |
2003年 | 6篇 |
2002年 | 14篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1963年 | 2篇 |
1961年 | 1篇 |
1960年 | 3篇 |
排序方式: 共有429条查询结果,搜索用时 14 毫秒
331.
Shanthi Muthuswamy Mario C. Vélez-Gallego Jairo Maya Miguel Rojas-Santiago 《The International Journal of Advanced Manufacturing Technology》2012,63(1-4):281-290
Given a set of jobs and two batch processing machines (BPMs) arranged in a flow shop environment, the objective is to batch the jobs and sequence the batches such that the makespan is minimized. The job sizes, ready times, and processing times on the two BPMs are known. The batch processing machines can process a batch of jobs as long as the total size of all the jobs assigned to a batch does not exceed its capacity. Once the jobs are batched, the processing time of the batch on the first machine is equal to the longest processing job in the batch; processing time of the batch on the second machine is equal to the sum of processing times of all the jobs in the batch. The batches cannot wait between two machines (i.e., no-wait). The problem under study is NP-hard. We propose a mathematical formulation and present a particle swarm optimization (PSO) algorithm. The solution quality and run time of PSO is compared with a commercial solver used to solve the mathematical formulation. Experimental study clearly highlights the advantages, in terms of solution quality and run time, of using PSO to solve large-scale problems. 相似文献
332.
Darya S. Novopashina Maya A. Dymova Anna S. Davydova Mariya I. Meschaninova Daria O. Malysheva Elena V. Kuligina Vladimir A. Richter Iaroslav A. Kolesnikov Sergey Yu. Taskaev Mariya A. Vorobyeva 《International journal of molecular sciences》2023,24(1)
Among the great variety of anti-cancer therapeutic strategies, boron neutron capture therapy (BNCT) represents a unique approach that doubles the targeting accuracy due to the precise positioning of a neutron beam and the addressed delivery of boron compounds. We have recently demonstrated the principal possibility of using a cell-specific 2′-F-RNA aptamer for the targeted delivery of boron clusters for BNCT. In the present study, we evaluated the amount of boron-loaded aptamer inside the cell via two independent methods: quantitative real-time polymerase chain reaction and inductive coupled plasma–atomic emission spectrometry. Both assays showed that the internalized boron level inside the cell exceeds 1 × 109 atoms/cell. We have synthesized closo-dodecaborate conjugates of 2′-F-RNA aptamers GL44 and Waz, with boron clusters attached either at the 3′- or at the 5′-end. The influence of cluster localization was evaluated in BNCT experiments on U-87 MG human glioblastoma cells and normal fibroblasts and subsequent analyses of cell viability via real-time cell monitoring and clonogenic assay. Both conjugates of GL44 aptamer provided a specific decrease in cell viability, while only the 3′-conjugate of the Waz aptamer showed the same effect. Thus, an individual adjustment of boron cluster localization is required for each aptamer. The efficacy of boron-loaded 2′-F-RNA conjugates was comparable to that of 10B-boronophenylalanine, so this type of boron delivery agent has good potential for BNCT due to such benefits as precise targeting, low toxicity and the possibility to use boron clusters made of natural, unenriched boron. 相似文献
333.
以碳化硅、硅粉为主要原料,以氧化铝和氧化钇为烧结助剂,通过添加不同质量分数的淀粉为造孔剂,采用反应烧结方式制备了系列氮化硅结合碳化硅多孔陶瓷支撑体,并对烧成样品的物相、显微结构、孔隙率、抗折强度、孔径分布、纯水通量和耐酸碱性能进行了分析和表征. 结果表明,样品的主晶相为碳化硅和氮化硅,还有少量的焦硅酸钇和塞隆;随着淀粉质量分数的增加,样品的孔隙率随之增大,样品的抗折强度随之减小,同时样品的平均孔径和纯水通量随淀粉质量分数的增加均呈现先增大后减小的趋势;样品有良好的耐酸碱性能,在标准酸性和碱性条件下的质量损失率分别为1.96%~2.04%、3.96%~4.13%;当淀粉的质量分数为3%时,烧成样品的孔隙率为41.8%,抗折强度为18.1 MPa,孔径主要分布在0.7 μm~2.5 μm之间,纯水通量最高,可达9.2 m3/(m2*h),综合性能较佳. 相似文献
334.
Bacteriophages have long been considered only as infectious agents that affect bacterial hosts. However, recent studies provide compelling evidence that these viruses are able to successfully interact with eukaryotic cells at the levels of the binding, entry and expression of their own genes. Currently, bacteriophages are widely used in various areas of biotechnology and medicine, but the most intriguing of them is cancer therapy. There are increasing studies confirming the efficacy and safety of using phage-based vectors as a systemic delivery vehicle of therapeutic genes and drugs in cancer therapy. Engineered bacteriophages, as well as eukaryotic viruses, demonstrate a much greater efficiency of transgene delivery and expression in cancer cells compared to non-viral gene transfer methods. At the same time, phage-based vectors, in contrast to eukaryotic viruses-based vectors, have no natural tropism to mammalian cells and, as a result, provide more selective delivery of therapeutic cargos to target cells. Moreover, numerous data indicate the presence of more complex molecular mechanisms of interaction between bacteriophages and eukaryotic cells, the further study of which is necessary both for the development of gene therapy methods and for understanding the cancer nature. In this review, we summarize the key results of research into aspects of phage–eukaryotic cell interaction and, in particular, the use of phage-based vectors for highly selective and effective systemic cancer gene therapy. 相似文献
335.
Maya Shofa Tomotaka Okamura Emiko Urano Yoshiharu Matsuura Yasuhiro Yasutomi Akatsuki Saito 《International journal of molecular sciences》2022,23(22)
Zika virus (ZIKV) outbreaks in Central and South America caused severe public health problems in 2015 and 2016. These outbreaks were finally contained through several methods, including mosquito control using insecticides and repellents. Additionally, the development of herd immunity in these countries might have contributed to containing the epidemic. While ZIKV is mainly transmitted by mosquito bites and mucosal transmission via bodily fluids, including the semen of infected individuals, has also been reported. We evaluated the effect of mucosal ZIKV infection on continuous subcutaneous challenges in a cynomolgus monkey model. Repeated intravaginal inoculations of ZIKV did not induce detectable viremia or clinical symptoms, and all animals developed a potent neutralizing antibody, protecting animals from the subsequent subcutaneous superchallenge. These results suggest that viral replication at mucosal sites can induce protective immunity without causing systemic viremia or symptoms. 相似文献
336.
Antoinette Tordesillas Maya Muthuswamy Stuart D. C. Walsh 《Canadian Metallurgical Quarterly》2008,134(12):1095-1113
We probe the origins of nonaffine deformation in discrete element simulations of densely packed granular systems under biaxial compression, using a new local measure of nonaffine micropolar deformation. This measure represents the deviation of particle motion from that dictated by a measure of micropolar strain and curvature, devised on the scale of a particle and its first ring of neighbors. Highly correlated mesoscopic structures emerge and contribute significantly to nonaffine deformation, an aspect of material behavior that is largely neglected in existing constitutive models. Distinct regimes of deformation were observed: a globally affine regime in which particles move in uncorrelated Brownian motion with some “rattlers” present followed by a globally nonaffine regime involving rattlers, microbands, vortices, confined buckling of force chains, and persistent shear band(s). Structural development leading to and during persistent shear banding is elucidated. The highest levels of nonaffine deformation were observed during drops in the macroscopic stress ratio: here, nonaffine deformation is essentially confined to the shear band, where confined buckling of force chains is the intrinsic mechanism. Degrees of correlation between the local measures of nonaffine strain and curvature confirm the key role of particle rotations in shear bands. Probability density functions of local nonaffine deformation exhibit power law behavior cut off by an exponential tail, consistent with experiments. Self-diffusion anisotropy was observed inside the shear band. The degree of diffusion is greater tangential rather than normal to the shear band; particles in buckling force chains exhibit the highest degree of diffusion along the band. Self-diffusion of particles after the peak stress ratio was found to be superdiffusive during each drop in stress ratio, and diffusive during each rise in stress ratio. The implications of these results for constitutive modeling are discussed, with particular attention paid to the significance of confined buckling of force chains. 相似文献
337.
One must consider both trait and state affect to predict individual differences in emotional processing. The present results document a novel trait-state interaction that is consistent with proposals concerning the epistemic functions of affect (A. R. Damasio, 1994). Four studies tested the effects of extraversion and mood on motivation-relevant processing. Study 1 measured naturally occurring mood, whereas Studies 2-4 manipulated mood. Extraverts were faster to link events to their personal motivations when in a positive mood state, whereas introverts were fast to do so in a neutral or negative mood state. Further findings indicate that this interaction affects attitude accessibility rather than event elaboration. Overall, the authors suggest that there are pragmatic benefits to trait-consistent moods, particularly for processing motivation-relevant stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
338.
Regiane Cristina Oliveira Mayara Mondego Teixeira João Paulo C. Costa Maya Penha Eric Mark Francisco Jussara Soares da Silva Máximo Siu Li Elson Longo Lourdes Gracia Juan Andrés 《Ceramics International》2018,44(6):5939-5944
Controlling the synthesis of a given polymorph of an inorganic material is a further step in the design of property and function. In this letter, we report for the first time a simple procedure to effectively control the reversible transformation between the crystalline polymorphs α-AgVO3 and β-AgVO3. Photoluminescence emission (PL) performance is analyzed; at low temperatures (up to 35 °C) when α-AgVO3 is formed the PL emission is red, while at temperatures larger than 45 °C when β-AgVO3 is obtained the color of emission PL emission goes from green to blue. The findings highlight the ability of temperature to dramatically alter the nature of phase transformation at the atomic level. The phase transformation is driven by the short-range structural and electronic changes of [VO4] and [AgOx] (x = 5, 6, and 7) clusters (building blocks of both monoclinic structures), and hence is dependent on the temperature employed during synthesis. These outcomes clearly demonstrate that the AgVO3 crystals exhibited appropriate activity for application in visible lamps, displays, and other optical devices. 相似文献
339.
Gautam Anand Meirav Leibman-Markus Dorin Elkabetz Maya Bar 《International journal of molecular sciences》2021,22(8)
Plants lack a circulating adaptive immune system to protect themselves against pathogens. Therefore, they have evolved an innate immune system based upon complicated and efficient defense mechanisms, either constitutive or inducible. Plant defense responses are triggered by elicitors such as microbe-associated molecular patterns (MAMPs). These components are recognized by pattern recognition receptors (PRRs) which include plant cell surface receptors. Upon recognition, PRRs trigger pattern-triggered immunity (PTI). Ethylene Inducing Xylanase (EIX) is a fungal MAMP protein from the plant-growth-promoting fungi (PGPF)–Trichoderma. It elicits plant defense responses in tobacco (Nicotiana tabacum) and tomato (Solanum lycopersicum), making it an excellent tool in the studies of plant immunity. Xylanases such as EIX are hydrolytic enzymes that act on xylan in hemicellulose. There are two types of xylanases: the endo-1, 4-β-xylanases that hydrolyze within the xylan structure, and the β-d-xylosidases that hydrolyze the ends of the xylan chain. Xylanases are mainly synthesized by fungi and bacteria. Filamentous fungi produce xylanases in high amounts and secrete them in liquid cultures, making them an ideal system for xylanase purification. Here, we describe a method for cost- and yield-effective xylanase production from Trichoderma using wheat bran as a growth substrate. Xylanase produced by this method possessed xylanase activity and immunogenic activity, effectively inducing a hypersensitive response, ethylene biosynthesis, and ROS burst. 相似文献