全文获取类型
收费全文 | 3243篇 |
免费 | 31篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 21篇 |
综合类 | 2篇 |
化学工业 | 184篇 |
金属工艺 | 43篇 |
机械仪表 | 34篇 |
建筑科学 | 28篇 |
矿业工程 | 1篇 |
能源动力 | 113篇 |
轻工业 | 62篇 |
水利工程 | 20篇 |
石油天然气 | 2篇 |
无线电 | 139篇 |
一般工业技术 | 327篇 |
冶金工业 | 2146篇 |
原子能技术 | 11篇 |
自动化技术 | 144篇 |
出版年
2022年 | 6篇 |
2021年 | 23篇 |
2020年 | 10篇 |
2019年 | 9篇 |
2018年 | 23篇 |
2017年 | 25篇 |
2016年 | 31篇 |
2015年 | 16篇 |
2014年 | 27篇 |
2013年 | 67篇 |
2012年 | 47篇 |
2011年 | 49篇 |
2010年 | 41篇 |
2009年 | 42篇 |
2008年 | 29篇 |
2007年 | 37篇 |
2006年 | 39篇 |
2005年 | 28篇 |
2004年 | 28篇 |
2003年 | 20篇 |
2002年 | 22篇 |
2001年 | 21篇 |
2000年 | 24篇 |
1999年 | 87篇 |
1998年 | 654篇 |
1997年 | 434篇 |
1996年 | 279篇 |
1995年 | 178篇 |
1994年 | 134篇 |
1993年 | 149篇 |
1992年 | 34篇 |
1991年 | 37篇 |
1990年 | 23篇 |
1989年 | 31篇 |
1988年 | 44篇 |
1987年 | 36篇 |
1986年 | 37篇 |
1985年 | 38篇 |
1984年 | 21篇 |
1983年 | 30篇 |
1982年 | 32篇 |
1981年 | 33篇 |
1980年 | 31篇 |
1979年 | 11篇 |
1978年 | 14篇 |
1977年 | 57篇 |
1976年 | 129篇 |
1975年 | 10篇 |
1974年 | 14篇 |
1973年 | 6篇 |
排序方式: 共有3277条查询结果,搜索用时 62 毫秒
101.
Distinct multicolored region descriptors for object recognition 总被引:1,自引:0,他引:1
Naik SK Murthy CA 《IEEE transactions on pattern analysis and machine intelligence》2007,29(7):1291-1296
102.
Economic pressures and "value" judgments both compel and contaminate the current debate on the efficacy of psychotherapy. Too often, complex clinical trial outcome studies ignore the clinical or treatment process, as well as personality or contextual variables. Thus, they fail to build the foundations of a clinical science that makes possible the development of individually tailored treatment approaches and outcome predictions for specific patients with unique personalities, symptoms, and life circumstances. The real challenge, therefore, is for each psychotherapeutic approach to delineate its "process steps" and relate these steps to different outcomes. The "process" is the "final common pathway" for a number of patient, therapist, technique, and contextual variables. The capacity to predict the relationship between process and outcome at each stage in a therapeutic procedure is the relevant clinical test of "efficacy." 相似文献
103.
beta-Ionone is found to stimulate considerably carotinoids synthesis in Blakeslea trispora. The stabilization of carotene-synthesizing ability of B. trispora in the presence of beta-ionine under prolonged incubation time is observed. Stabilization of polyribosomes in the presence of beta-ionine is observed when studying polyribosome content in B. trispora. A hypothesis is expressed on the existence of biochemical "receptors" as a linkage between synthesized protein and destroying mRNA. 相似文献
104.
G. Manimaran C. Siva Ram Murthy Machiraju Vijay Krithi Ramamritham 《Journal of Parallel and Distributed Computing》1997,44(2):365
The scheduling of tasks in multiprocessor real-time systems has attracted many researchers in the recent past. Tasks in these systems have deadlines to be met, and most of the real-time scheduling algorithms use worst case computation times to schedule these tasks. Many resources will be left unused if the tasks are dispatched purely based on the schedule produced by these scheduling algorithms, since most of the tasks will take less time to execute than their respective worst case computation times. Resource reclaiming refers to the problem of reclaiming the resources left unused by a real-time task when it takes less time to execute than its worst case computation time. In this paper, we propose two algorithms to reclaim these resources from real-time tasks that are constrained by precedence relations and resource requirements, in shared memory multiprocessor systems. We introduce a notion called a restriction vector for each task which captures its resource and precedence constraints with other tasks. This will help not only in the efficient implementation of the algorithms, but also in obtaining an improvement in performance over the reclaiming algorithms proposed in earlier work [[2]]. We compare our resource reclaiming algorithms with the earlier algorithms and, by experimental studies, show that they reclaim more resources, thereby increasing the guarantee ratio (the ratio of the number of tasks guaranteed to meet their deadlines to the number of tasks that have arrived), which is the basic requirement of any resource reclaiming algorithm. From our simulation studies, we demonstrate that complex reclaiming algorithms with high reclaiming overheads do not lead to an improvement in the guarantee ratio. 相似文献
105.
Piriyakumar D.A.L. Murthy C.S.R. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》1998,28(2):245-251
In this paper, the problem of optimal distribution of measurement data to be processed in minimal time on a hypercube network of sensor driven processors is considered. An analytical model is developed for solving the problem efficiently. Unlike the previous models, this model considers: 1) explicitly the setup time which constrains exploiting all the available processors; 2) simultaneous use of links to expedite the communication; 3) partial solution combining time to encompass wider class of related problems. By deriving a lower bound on the amount of data to be received by a processor for efficient distribution, a new technique called fractal hypercube is introduced here to get the optimal solution with fewer processors, An optimal iterative method for hypercubes and a near-optimal recursive method with a refinement are presented for the same with the analysis. The effect of varying the originating processor and the choice of fractal hypercube are discussed with an effective technique called processor isomorphism. This study reveals that always the fractal hypercubes outperform the other two methods, the optimal iterative method for hypercubes and the near-optimal method 相似文献
106.
The performance modeling study of Delay-Tolerant Network routing, in general, assumes the nodes to be homogeneous (in terms of features such as the coverage range) and uncompromised (in terms of forwarding messages). However, in realistic settings this may not be the case. The routing performance modeling of such realistic scenarios that involve multifariously-featured and egotistic nodes would be interesting and insightful. To this end, in this paper, we analytically model the routing behavior of such nodes using Ordinary Differential Equations for two different routing protocols namely, Epidemic Routing and Two-Hop Routing. Furthermore, we also study the degradation in the routing performance caused by an increase in the fraction of selfish nodes present in the heterogeneous node population. The proposed analytical model is validated via extensive simulations. 相似文献
107.
Amodini Mishra S. N. Choudhary R. N. P. Choudhary V. R. K. Murthy Kamal Prasad 《Journal of Materials Science: Materials in Electronics》2012,23(1):185-192
A new lead-free perovskite Ba(Bi1/2Ta1/2)O3 was prepared by conventional ceramic fabrication technique at 1,200 °C/4 h in air atmosphere. The crystal symmetry, space
group and unit cell dimensions were determined from the experimental results using FullProf software. The crystallite size
and lattice strain were estimated from Williamson-Hall approach. XRD analysis of the compound indicated the formation of a
single-phase cubic structure with the space group Pm3m. EDAX and SEM studies were carried out in order to evaluate the quality and purity of the compound. Permittivity data showed
a low temperature coefficient of capacitance (T
CC
< 4%) up to +125 °C. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. Electric modulus
studies supported the hopping type of conduction in Ba(Bi1/2Ta1/2)O3. 相似文献
108.
Thrupathihalli Pandurangapp Krishna Murthy Balaraman Manohar 《International Journal of Food Science & Technology》2012,47(6):1229-1236
Curcuma amada (Mango ginger) was dried at four different power levels ranging 315–800 W to determine the effect of microwave power on moisture content, moisture ratio, drying rate, drying time and effective diffusivity. Among the fifteen thin layer drying models considered for evaluating the drying behaviour, the semi‐empirical Midilli et al., model described the drying kinetics very well with R2 > 0.999. Drying rate and effective diffusivity increased as the microwave power output increased. Activation energy was estimated by a modified Arrhenius type equation and found to be 21.6 kW kg?1. A feed‐forward artificial neural network using back‐propagation algorithm was also employed to predict the moisture content during MW drying and found adequate to predict the drying kinetics with R2 of 0.985. 相似文献
109.
110.