全文获取类型
收费全文 | 720064篇 |
免费 | 8895篇 |
国内免费 | 1499篇 |
专业分类
电工技术 | 13152篇 |
综合类 | 632篇 |
化学工业 | 111352篇 |
金属工艺 | 32521篇 |
机械仪表 | 23856篇 |
建筑科学 | 15977篇 |
矿业工程 | 5600篇 |
能源动力 | 17822篇 |
轻工业 | 54684篇 |
水利工程 | 9072篇 |
石油天然气 | 18219篇 |
武器工业 | 52篇 |
无线电 | 76458篇 |
一般工业技术 | 150479篇 |
冶金工业 | 120411篇 |
原子能技术 | 17600篇 |
自动化技术 | 62571篇 |
出版年
2021年 | 6513篇 |
2019年 | 6200篇 |
2018年 | 14704篇 |
2017年 | 14936篇 |
2016年 | 13974篇 |
2015年 | 7368篇 |
2014年 | 12151篇 |
2013年 | 31209篇 |
2012年 | 19924篇 |
2011年 | 28995篇 |
2010年 | 23882篇 |
2009年 | 25548篇 |
2008年 | 26152篇 |
2007年 | 26852篇 |
2006年 | 19464篇 |
2005年 | 19280篇 |
2004年 | 17814篇 |
2003年 | 17353篇 |
2002年 | 16191篇 |
2001年 | 15496篇 |
2000年 | 14906篇 |
1999年 | 14624篇 |
1998年 | 34808篇 |
1997年 | 24983篇 |
1996年 | 19439篇 |
1995年 | 14829篇 |
1994年 | 13345篇 |
1993年 | 13174篇 |
1992年 | 10156篇 |
1991年 | 9868篇 |
1990年 | 9633篇 |
1989年 | 9363篇 |
1988年 | 9116篇 |
1987年 | 8146篇 |
1986年 | 7997篇 |
1985年 | 9067篇 |
1984年 | 8218篇 |
1983年 | 7903篇 |
1982年 | 7120篇 |
1981年 | 7165篇 |
1980年 | 6960篇 |
1979年 | 7081篇 |
1978年 | 6959篇 |
1977年 | 7646篇 |
1976年 | 9423篇 |
1975年 | 6251篇 |
1974年 | 5988篇 |
1973年 | 6121篇 |
1972年 | 5308篇 |
1971年 | 4951篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Malloy B.A. Lloyd E.L. Soffa M.L. 《Parallel and Distributed Systems, IEEE Transactions on》1994,5(5):498-508
A new approach is given for scheduling a sequential instruction stream for execution “in parallel” on asynchronous multiprocessors. The key idea in our approach is to exploit the fine grained parallelism present in the instruction stream. In this context, schedules are constructed by a careful balancing of execution and communication costs at the level of individual instructions, and their data dependencies. Three methods are used to evaluate our approach. First, several existing methods are extended to the fine grained situation. Our approach is then compared to these methods using both static schedule length analyses, and simulated executions of the scheduled code. In each instance, our method is found to provide significantly shorter schedules. Second, by varying parameters such as the speed of the instruction set, and the speed/parallelism in the interconnection structure, simulation techniques are used to examine the effects of various architectural considerations on the executions of the schedules. These results show that our approach provides significant speedups in a wide-range of situations. Third, schedules produced by our approach are executed on a two-processor Data General shared memory multiprocessor system. These experiments show that there is a strong correlation between our simulation results, and these actual executions, and thereby serve to validate the simulation studies. Together, our results establish that fine grained parallelism can be exploited in a substantial manner when scheduling a sequential instruction stream for execution “in parallel” on asynchronous multiprocessors 相似文献
992.
Pipelining and bypassing in a VLIW processor 总被引:1,自引:0,他引:1
This short note describes issues involved in the bypassing mechanism for a very long instruction word (VLIW) processor and its relation to the pipeline structure of the processor. The authors first describe the pipeline structure of their processor and analyze its performance and compare it to typical RISC-style pipeline structures given the context of a processor with multiple functional units. Next they study the performance effects of various bypassing schemes in terms of their effectiveness in resolving pipeline data hazards and their effect on the processor cycle time 相似文献
993.
We present a method for analyzing the convergence properties of nonlinear dynamical systems yielding second-order bounds on the domain of attraction of an asymptotically stable equilibrium point and on the time of convergence in the estimated domain. We show that under certain conditions on the system, there exists an analytic solution to the corresponding optimization problem. The method is applied in analyzing the dynamics of a neural network model. 相似文献
994.
This paper addresses the existence of loop gain-phase shaping (LGPS) solutions for the design of robust digital control systems for SISO, minimum-phase, continuous-time processes with parametric uncertainty. We develop the frequency response properties of LGPS for discrete-time systems using the Δ-transform, a transform method that applies to both continuous-time and discrete-time systems. A theorem is presented which demonstrates that for reasonable specifications there always exists a sampling period such that the robust digital control problem has a solution. Finally, we offer a procedure for estimating the maximum feasible sampling period for LGPS solutions to robust digital control problems. 相似文献
995.
Russel B. Miller Isaac M. Horowitz Constantine H. Houpis A. Finley Barfield 《国际强度与非线性控制杂志
》1994,4(1):211-230
》1994,4(1):211-230
Nonlinear quantitative feedback theory (QFT) and pilot compensation techniques are used to design a 2 × 2 flight control system for the YF-16 aircraft over a large range of plant uncertainty. The design is based on numerical input-output time histories generated with a FORTRAN implemented nonlinear simulation of the YF-16. The first step of the design process is the generation of a set of equivalent linear time-invariant (LTI) plant models to represent the actual nonlinear plant. It has been proven that the solution to the equivalent plant problem is guaranteed to solve the original nonlinear problem. Standard QFT techniques are then used in the design synthesis based on the equivalent plant models. A detailed mathematical development of the method used to develop these equivalent LTI plant models is provided. After this inner-loop design, pilot compensation is developed to reduce the pilot's workload. This outer-loop design is also based on a set of equivalent LTI plant models. This is accomplished by modelling the pilot with parameters that result in good handling qualities ratings, and developing the necessary compensation to force the desired system responses. 相似文献
996.
Storment C.W. Borkholder D.A. Westerlind V. Suh J.W. Maluf N.I. Kovacs G.T.A. 《Journal of microelectromechanical systems》1994,3(3):90-96
We present an all-aluminum MEMS process (Al-MEMS) for the fabrication of large-gap electrostatic actuators with process steps that are compatible with the future use of underlying, pre-fabricated CMOS control circuitry. The process is purely additive above the substrate as opposed to processes that depend on etching pits into the silicon, and thereby permits a high degree of design freedom. Multilayer aluminum metallization is used with organic sacrificial layers to build up the actuator structures. Oxygen-based dry etching is used to remove the sacrificial layers. While this approach has been previously used by other investigators to fabricate optical modulators and displays, the specific process presented herein has been optimized for driving mechanical actuators with relatively large travels. The process is also intended to provide flexibility for design and future enhancements. For example, the gap height between the actuator and the underlying electrode(s) can be set using an adjustable polyimide sacrificial layer and aluminum “post” deposition step. Several Al-MEMS electrostatic structures designed for use as mechanical actuators are presented as well as some measured actuation characteristics 相似文献
997.
Chris Gibbons Corrine Chaves Ronald B. Wilkes Mark N. Frolick 《Information Systems Management》1994,11(3):51-56
Information-based organizations are structured to function with as small and efficient a staff as possible. To this end, executives at The Promus Companies are using IT to spread decision-making authority and responsibility for customer satisfaction and customer service throughout the organization. 相似文献
998.
What is the implication for business when information technology (IT) changes in the workplace without a commensurate change in the composition of business programs educating tomorrow's employees? A survey of MBA graduates forms the basis of this article on the IT skills needed in the marketplace. 相似文献
999.
A. N. Prikhod'ko 《Cybernetics and Systems Analysis》1994,30(4):591-603
Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 140–155, July–August 1994. 相似文献
1000.