全文获取类型
收费全文 | 454篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
综合类 | 2篇 |
化学工业 | 102篇 |
金属工艺 | 9篇 |
机械仪表 | 10篇 |
建筑科学 | 6篇 |
矿业工程 | 2篇 |
能源动力 | 23篇 |
轻工业 | 56篇 |
水利工程 | 5篇 |
石油天然气 | 9篇 |
无线电 | 50篇 |
一般工业技术 | 93篇 |
冶金工业 | 25篇 |
原子能技术 | 10篇 |
自动化技术 | 64篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 27篇 |
2021年 | 25篇 |
2020年 | 26篇 |
2019年 | 23篇 |
2018年 | 25篇 |
2017年 | 21篇 |
2016年 | 28篇 |
2015年 | 20篇 |
2014年 | 23篇 |
2013年 | 39篇 |
2012年 | 22篇 |
2011年 | 21篇 |
2010年 | 9篇 |
2009年 | 16篇 |
2008年 | 19篇 |
2007年 | 21篇 |
2006年 | 8篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有473条查询结果,搜索用时 15 毫秒
401.
Mukta Tyagi Amit Choudhary Santosh K. Upadhyay Ved V. Agrawal 《Integrated ferroelectrics》2017,184(1):55-68
ABSTRACTWe have investigated alpha (α) relaxation process and its temperature evolution in electrical double layer (EDL) around neutrophil gelatinase-associated lipocalin (NGAL), anti-lipocalin2 (anti-LCN-2) and their conjugate in phosphate buffer. The dielectric permittivity (20 Hz to 1 MHz) of α-relaxation process for LCN-2 and anti-LCN-2 shows variation with temperature. This happens due to unfolding of various microstates of protein at measured temperature intervals. The DSC thermograms of LCN-2, anti-LCN-2 and their conjugate predict that the multiple unfolding domains are parallel to the shifts in real dielectric permittivity at a particular temperature. 相似文献
402.
Amandeep Kaur Alok Sharma Madhu Sameer Dixit Kashmir Singh Santosh Kumar Upadhyay 《International journal of molecular sciences》2022,23(23)
The hyperosmolality-gated calcium-permeable channels (OSCA) are pore-forming transmembrane proteins that function as osmosensors during various plant developmental processes and stress responses. In our analysis, through in silico approaches, a total of 42 OSCA genes are identified in the Triticum aestivum genome. A phylogenetic analysis reveals the close clustering of the OSCA proteins of Arabidopsis thaliana, Oryza sativa, and T. aestivum in all the clades, suggesting their origin before the divergence of dicots and monocots. Furthermore, evolutionary analyses suggest the role of segmental and tandem duplication events (Des) and purifying selection pressure in the expansion of the OSCA gene family in T. aestivum. Expression profiling in various tissue developmental stages and under abiotic and biotic stress treatments reveals the probable functioning of OSCA genes in plant development and the stress response in T. aestivum. In addition, protein–protein and protein–chemical interactions reveal that OSCA proteins might play a putative role in Ca2+-mediated developmental processes and adaptive responses. The miRNA interaction analysis strengthens the evidence for their functioning in various biological processes and stress-induced signaling cascades. The current study could provide a foundation for the functional characterization of TaOSCA genes in future studies. 相似文献
403.
A new method is proposed for evaluating accurate incabinet response spectra for seismic qualification of electrical instruments. Finite element analysis of several typical cabinets shows that only few (often one) modes contribute significantly to the spectral accelerations at critical instrument locations inside the cabinet. In most cases the significant mode is a local mode of the cabinet component like door or back wall on which the instrument is mounted. In some cases it can also be a global cabinet mode or a superposition of the global cabinet and local component modes. Dynamic properties of the significant modes can be calculated using Rayleigh–Ritz method. The engineering effort and computational time taken by the new method is a minute fraction of that by the finite element method. 相似文献
404.
The quadrature method of moments (QMOM) has been widely used for the simulation of the evolution of moments of the aerosol general dynamic equations. However, there are several shortcomings in a crucial component of the method, the product-difference (P-D) algorithm. The P-D algorithm is used to compute the quadrature points and weights from the moments of an unknown distribution. The algorithm does not work for all types of distributions or for even reasonably high-order quadrature. In this work, we investigate the use of the Chebyshev algorithm and show that it is more robust than the P-D algorithm and can be used for a wider class of problems. The algorithm can also be used in a number of applications, where accurate computations of weighted integrals are required. We also illustrate the use of QMOM with the Chebyshev algorithm to solve several problems in aerosol science that could not be solved using the P-D algorithm. 相似文献
405.
The use of greener additives based on vegetable oils in the formulation of bio-lubricant has attracted considerable interest due to their biocompatibility and enhanced multifunctional performances compared to conventional additives. Working in this direction and in an anticipation of introducing biodegradability in to the acrylate based additive system, copolymers of isodecyl acrylate with olive oil have been synthesized by thermal method using BPO (benzoyl peroxide) as radical initiator. Characterization of the prepared polymers has been performed by spectral (NMR, IR), and SEC-GPC analysis. Performance evaluation of the polymers as pour point depressant (PPD), and viscosity modifier/viscosity index improver (VII) in different base oils (mineral) have been performed by standard ASTM methods. Biodegradability of the prepared additives was tested against fungal pathogens and microorganisms by disc diffusion (DD) method and by soil burial test (SBT) method respectively. Thermal stability of each of them has been evaluated and included. The multifunctional performances have been compared and reported. The copolymers showed potential multifunctional additive performance as viscosity modifier and pour point depressant along with excellent biodegradability. 相似文献
406.
Claude Sinner Benjamin Lutz Shalini John Ines Reinartz Abhinav Verma Alexander Schug 《Israel journal of chemistry》2014,54(8-9):1165-1175
The 2013 Nobel Prize in Chemistry highlights how crucial computer simulations have become for many scientific and engineering fields. Nowadays, scientific progress is not only driven by the interplay of new experimental measurements and increasingly sophisticated theoretical frameworks, but also by an incredible toolbox of complex computational models meeting ubiquitously available computing power and data storage facilities. Quantum mechanical (QM) calculations can be condensed into molecular mechanics (MM) force fields and coupled QM/MM calculations can derive atomic and molecular properties of biomolecular or materials science systems with high accuracy. Pure MM simulations driven by Monte Carlo or molecular dynamics algorithms are widely applied in biological chemistry/physics and can investigate large biomolecular systems, such as proteins, DNA, or RNA. One coarse-grained class of these models, native-structure-based or Go models, are based on energy landscape theory and the principle of minimal frustration. Herein, an ensemble of converging pathways guide protein folding on a funnel-like shape of the entire energy landscape towards the native state. Simulations based on these ideas have been tremendously successful in explaining protein folding and function. Their history and recent application highlights are reviewed. 相似文献
407.
Correlation coefficients for modal response combination of non-classically damped systems 总被引:1,自引:0,他引:1
Correlation coefficients to perform modal combination of responses for non-classically damped systems are studied. The frequency domain analysis method is used to calculate the coefficients for 12 earthquake records and 10 damping ratios. The response of non-classically damped systems is evaluated for a range of frequencies between completely rigid and completely non-rigid. It is found that the earlier proposed linear relationship of the rigid response coefficient with frequency on a semilogarithmic graph is not accurate and that the rigid response coefficient is a function of the damping ratio. New expressions for determining the rigid response coefficients for displacement and velocity responses are proposed. The related key frequencies are also studied and found to be different from those proposed in the earlier studies. New formulations for determining these frequencies are presented. Modified equations for correlation coefficients proposed in this study are found to yield good agreement with the numerically evaluated displacement and velocity correlation coefficients for all frequency ranges. Further investigation is needed for the cross-correlation coefficient to improve the agreement with numerical results in the high frequency range. 相似文献
408.
Several plate models have been proposed in the literature for the analysis of laminated plates. These are based either on an equivalent through-thickness formulation or a layerwise formulation. It is shown in the literature that while the equivalent models are economical, the layerwise models are expensive but are also more accurate, especially with respect to the transverse stresses. Generally, the same model is used throughout the domain. The current study addresses the issue of economical and accurate computation of local stresses, strains and displacements (as well as global quantities) using combinations of layerwise, equivalent or intermediate models in various regions of the domain. A region-by-region modeling strategy is presented for a chosen general family of equivalent, intermediate and layerwise models. The proposed strategy allows the user to put any model (of any order in the thickness direction) in any desired region of interest. The effectiveness of the strategy is demonstrated through numerical examples. It is shown that this approach can significantly reduce computational cost and can also lead to good resolution of the local stress and displacement fields for domains with unsymmetric laminae, cut-outs, local damage, corner edges, sudden transition of boundary conditions and material. 相似文献
409.
Simon Taylor Drona Upadhyay Maria Laguna 《小水电新闻》2006,23(1):11-15
While the growth of small hydro has slowed in Europe, things look very different in Asia. The region accounts for two-thirds of the world's hydro capacity, and far from slowing down, it is enjoying robust growth. Simon Taylor, Drona Upadhyay and Maria Laguna write this review. 相似文献
410.