全文获取类型
收费全文 | 1669篇 |
免费 | 71篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 24篇 |
综合类 | 2篇 |
化学工业 | 371篇 |
金属工艺 | 45篇 |
机械仪表 | 50篇 |
建筑科学 | 31篇 |
矿业工程 | 2篇 |
能源动力 | 90篇 |
轻工业 | 119篇 |
水利工程 | 15篇 |
石油天然气 | 4篇 |
无线电 | 220篇 |
一般工业技术 | 390篇 |
冶金工业 | 168篇 |
原子能技术 | 19篇 |
自动化技术 | 201篇 |
出版年
2024年 | 7篇 |
2023年 | 29篇 |
2022年 | 80篇 |
2021年 | 104篇 |
2020年 | 84篇 |
2019年 | 59篇 |
2018年 | 101篇 |
2017年 | 66篇 |
2016年 | 82篇 |
2015年 | 53篇 |
2014年 | 70篇 |
2013年 | 126篇 |
2012年 | 68篇 |
2011年 | 82篇 |
2010年 | 67篇 |
2009年 | 42篇 |
2008年 | 48篇 |
2007年 | 62篇 |
2006年 | 31篇 |
2005年 | 27篇 |
2004年 | 21篇 |
2003年 | 14篇 |
2002年 | 26篇 |
2001年 | 24篇 |
2000年 | 14篇 |
1999年 | 18篇 |
1998年 | 38篇 |
1997年 | 42篇 |
1996年 | 26篇 |
1995年 | 13篇 |
1994年 | 15篇 |
1993年 | 16篇 |
1992年 | 11篇 |
1991年 | 14篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 16篇 |
1973年 | 5篇 |
排序方式: 共有1751条查询结果,搜索用时 15 毫秒
21.
22.
Generalized Bonferroni Mean Operator for Fuzzy Number Intuitionistic Fuzzy Sets and its Application to Multiattribute Decision Making 下载免费PDF全文
Rajkumar Verma 《国际智能系统杂志》2015,30(5):499-519
The Bonferroni mean (BM) was originally introduced by Bonferroni in 1950. A prominent characteristic of BM is its capability to capture the interrelationship between input arguments. This makes BM useful in various application fields, such as decision making, information retrieval, pattern recognition, and data mining. In this paper, we examine the issue of fuzzy number intuitionistic fuzzy information fusion. We first propose a new generalized Bonferroni mean operator called generalized fuzzy number intuitionistic fuzzy weighted Bonferroni mean (GFNIFWBM) operator for aggregating fuzzy number intuitionistic fuzzy information. The properties of the new aggregation operator are studied and their special cases are examined. Furthermore, based on the GFNIFWBM operator, an approach to deal with multiattribute decision‐making problems under fuzzy number intuitionistic fuzzy environment is developed. Finally, a practical example is provided to illustrate the multiattribute decision‐making process. 相似文献
23.
Michael M. Li Brijesh Verma Xiaolong Fan Kevin Tickle 《Neural computing & applications》2008,17(4):391-397
This paper investigates a new method to solve the inverse problem of Rutherford backscattering (RBS) data. The inverse problem
is to determine the sample structure information from measured spectra, which can be defined as a function approximation problem.
We propose using radial basis function (RBF) neural networks to approximate an inverse function. Each RBS spectrum, which
may contain up to 128 data points, is compressed by the principal component analysis, so that the dimensionality of input
data and complexity of the network are reduced significantly. Our theoretical consideration is tested by numerical experiments
with the example of the SiGe thin film sample and corresponding backscattering spectra. A comparison of the RBF method with
multilayer perceptrons reveals that the former has better performance in extracting structural information from spectra. Furthermore,
the proposed method can handle redundancies properly, which are caused by the constraint of output variables. This study is
the first method based on RBF to deal with the inverse RBS data analysis problem. 相似文献
24.
Yadav Vijay Kumar Yadav Rakesh Kumar Verma Shekhar Venkatesan S. 《The Journal of supercomputing》2022,78(2):2386-2416
The Journal of Supercomputing - In the Attribute-Based Encryption (ABE) scheme, patients encrypt their electronic health record (EHR), attach the appropriate attributes with it, and outsource them... 相似文献
25.
K. Rajakumari M.Vinoth Kumar Garima Verma S. Balu Dilip Kumar Sharma Sudhakar Sengan 《计算机系统科学与工程》2022,40(2):581-592
Cloud computing is an Information Technology deployment model established on virtualization. Task scheduling states the set of rules for task allocations to an exact virtual machine in the cloud computing environment. However, task scheduling challenges such as optimal task scheduling performance solutions, are addressed in cloud computing. First, the cloud computing performance due to task scheduling is improved by proposing a Dynamic Weighted Round-Robin algorithm. This recommended DWRR algorithm improves the task scheduling performance by considering resource competencies, task priorities, and length. Second, a heuristic algorithm called Hybrid Particle Swarm Parallel Ant Colony Optimization is proposed to solve the task execution delay problem in DWRR based task scheduling. In the end, a fuzzy logic system is designed for HPSPACO that expands task scheduling in the cloud environment. A fuzzy method is proposed for the inertia weight update of the PSO and pheromone trails update of the PACO. Thus, the proposed Fuzzy Hybrid Particle Swarm Parallel Ant Colony Optimization on cloud computing achieves improved task scheduling by minimizing the execution and waiting time, system throughput, and maximizing resource utilization. 相似文献
26.
Cost-effective valorization of carbon dioxide into bulk and specialty chemicals using catalysis will be attractive in the foreseeable future. 1,3-Oxazolidin-2-one derivatives are one of the important classes of heterocyclic compounds which have wide applications in pharmaceutical industries due to their biological activities such as antibacterial, antimicrobial, antiseptic. Various synthetic routes are employed to prepare these compounds which include phosgenation, oxidative carbonylation, etc., which make use of polluting chemicals and homogeneous catalysts. The heterogeneous catalytic processes to synthesize these derivatives are quite limited. Thus, developing a green route which is environmental friendly is highly desirable. The current work deals with development of a heterogeneous reusable catalyst and its application to synthesize 1,3-oxazolidin-2-one derivatives using carbon dioxide as a C1 source. The fact that no use of promoter or organic co-catalyst is made in the current process makes the synthesis route more favorable. Pure La–MgO and K–La–MgO with different K loading (1, 3, 5, and 7 wt%) synthesized by combustion route were screened for carbonylation of diethanol amine. 5% K–La–MgO was found to be the best catalyst. The catalyst was well characterized in virgin form and after use by various analytical techniques like TEM, SEM, XRD, CO2 and NH3-TPD, BET surface area analysis. With 5% K–La/MgO, 72% conversion of diethanol amine was achieved with 100% selectivity of the desired product at optimum conditions, i.e., 150 °C, 5 wt% K–La/MgO catalyst loading of 0.02 g/cm3 and 2.0 MPa CO2 pressure. Reaction mechanism was proposed and kinetic model developed. The apparent activation energy was calculated as 18.76 kcal/mol. The catalyst was robust and recyclable. The process is clean and green. 相似文献
27.
A. S. Ibraheam Y. Al-Douri J. M. S. Al-Fhdawi Hamid S. AL-Jumaili K. D. Verma U. Hashim R. M. Ayub A. Rahim Ruslinda M. K. Md Arshad A. H. Reshak S. B. Abd Hamid 《Microsystem Technologies》2016,22(12):2893-2900
The Cu2Zn1?xCdxSnS4 quinternary alloy nanostructures with different Cd contents were grown using spin coating technique on porous silicon (63.93 %) substrate. The structural properties of Cu2Zn1?xCdxSnS4/PS were investigated by X-ray diffraction and field emission-scanning electron microscope (FE-SEM). The optical properties studied through photoluminescence technique, indicated that the band gap is shifted as Cd content increases from 1.84 eV at x = 0 to 1.76 eV at x = 1. The electrical characterization of the Ag/n-PS/Cu2Zn1?xCdxSnS4/Ag diode through current to voltage (I–V) characterization shows the highest photo-response of (value if any) at Cu2Zn0.4Cd0.6SnS4 composition. 相似文献
28.
A novel bacterial foraging technique for edge detection 总被引:2,自引:0,他引:2
Om Prakash Verma Madasu HanmandluPuneet Kumar Sidharth ChhabraAkhil Jindal 《Pattern recognition letters》2011,32(8):1187-1196
A new approach for edge detection using a combination of bacterial foraging algorithm (BFA) and probabilistic derivative technique derived from Ant Colony Systems, is presented in this paper. The foraging behavior of some species of bacteria like Escherichia coli can be hypothetically modeled as an optimization process. A group of bacteria search for nutrients in a way that maximizes the energy obtained per unit time spent during the foraging. The proposed approach aims at driving the bacteria through the edge pixels. The direction of movement of the bacteria is found using a direction probability matrix, computed using derivatives along the possible directions. Rules defining the derivatives are devised to ensure that the variation of intensity due to noise is discarded. Quantitative analysis of the feasibility of the proposed approach and its comparison with other standard edge detection operators in terms of kappa and entropy are given. The effect of initial values of parameters of BFA on the edge detection is discussed. 相似文献
29.
We report the design and development of insulated gate bipolar junction transistor based high performance driver for operating thyratrons in grounded grid mode. With careful design, the driver meets the specification of trigger output pulse rise time less than 30 ns, jitter less than +/-1 ns, and time delay less than 160 ns. It produces a -600 V pulse of 500 ns duration (full width at half maximum) at repetition rate ranging from 1 Hz to 1.14 kHz. The developed module also facilitates heating and biasing units along with protection circuitry in one complete package. 相似文献
30.
The Internet infrastructure must evolve from best-effort service to meet the needs of different customers and applications. With Internet traffic differentiation, service providers can support a range of offerings, such as loss or delay bounds and network bandwidth allocation, to meet different performance requirements. The differentiated services (Diffserv) architecture provides a scalable approach, in which network access (or edge) devices aggregate traffic flows onto provisioned pipes that traverse a streamlined network core. We have identified the key requirements for provisioning Diffserv functions on Internet servers. Based on these requirements, we have implemented, and deployed, a policy-based architecture on IBM's AIX operating system that provides Diffserv services to both QoS-aware and -unaware applications 相似文献