首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   10540篇
  免费   332篇
  国内免费   571篇
电工技术   147篇
综合类   10篇
化学工业   2333篇
金属工艺   300篇
机械仪表   192篇
建筑科学   456篇
矿业工程   54篇
能源动力   304篇
轻工业   686篇
水利工程   114篇
石油天然气   201篇
武器工业   32篇
无线电   676篇
一般工业技术   1807篇
冶金工业   1866篇
原子能技术   632篇
自动化技术   1633篇
  2022年   89篇
  2021年   149篇
  2020年   120篇
  2019年   115篇
  2018年   160篇
  2017年   159篇
  2016年   202篇
  2015年   174篇
  2014年   256篇
  2013年   728篇
  2012年   396篇
  2011年   508篇
  2010年   374篇
  2009年   403篇
  2008年   453篇
  2007年   400篇
  2006年   406篇
  2005年   341篇
  2004年   329篇
  2003年   272篇
  2002年   288篇
  2001年   201篇
  2000年   186篇
  1999年   183篇
  1998年   250篇
  1997年   213篇
  1996年   186篇
  1995年   152篇
  1994年   160篇
  1993年   251篇
  1992年   149篇
  1991年   192篇
  1990年   176篇
  1989年   199篇
  1988年   170篇
  1987年   194篇
  1986年   210篇
  1985年   142篇
  1984年   165篇
  1983年   118篇
  1982年   117篇
  1981年   95篇
  1980年   92篇
  1979年   100篇
  1978年   83篇
  1977年   102篇
  1976年   98篇
  1975年   87篇
  1974年   92篇
  1973年   75篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Coordinating production and distribution of jobs with bundling operations   总被引:1,自引:0,他引:1  
We consider an integrated scheduling and distribution model in which jobs completed by two different machines must be bundled together for delivery. The objective is to minimize the sum of the delivery cost and customers' waiting costs. Such a model not only attempts to coordinate the job schedules on both machines, but also aims to coordinate the machine schedules with the delivery plan. Polynomial-time heuristics and approximation schemes are developed for the model with only direct shipments as well as the general model with milk-run deliveries.  相似文献   
42.
Effects of constant voltage stress (CVS) on gate stacks consisting of an ALD HfO2 dielectric with various interfacial layers were studied with time dependent sensing measurements: DC IV, pulse IV, and charge pumping (CP) at different frequencies. The process of injected electron trapping/de-trapping on pre-existing defects in the bulk of the high-κ film was found to constitute the major contribution to the time dependence of the threshold voltage (Vt) shift during stress. The trap generation observed with the low frequency CP measurements is suggested to occur within the interfacial oxide layer or the interfacial layer/high-κ interface, with only a minor effect on Vt.  相似文献   
43.
44.
45.
X-ray diffraction and ab initio MO theoretical calculations were used in order to investigate the structural and electronic properties of sarmazenil, a weak inverse agonist at the omega modulatory sites (benzodiazepine receptors). This compound was compared to bretazenil, a partial agonist, and to the antagonist flumazenil on the basis of structural and electronic data. The conformational and theoretical properties (interatomic pi overlap populations, molecular electrostatic potential (MEP), the topology of frontier orbitals, and proton affinity) of these three imidazobenzodiazepinones were determined in order to analyse the stereoelectronic properties in relation with their distinct intrinsic efficacies at the omega modulatory sites.  相似文献   
46.
Batch-means control charts for autocorrelated data   总被引:2,自引:0,他引:2  
Modern statistical process control must often cope with large quantities of highly autocorrelated data. Alwan and Radson (1992) proposed the monitoring of autocorrelated processes by plotting the averages of small batches of data separated by skipping observations. Using results for the AR(1) process, we show that generally better performance can be achieved with no skipping and much larger batch sizes. The resulting batch-means charts derive from methods used in simulation output analysis and can be implemented easily with common digital control systems.  相似文献   
47.
48.
This paper demonstrates how the problem of tracking targets, which appear as either straight or curved lines in two-dimensional display images (or data images) can be formulated in terms of a directed weighted graph model and how dynamic programming techniques can be efficiently applied to reach an optimal or sub-optimal solution. In general, track detection algorithms providing optimal solutions have good detective ability, but most of them suffer from the inability to detect discontinuous lines or to resolve efficiently pairs of crossing lines. A sub-optimal solution is provided that efficiently overcomes these weaknesses. We focus on modeling the track detection problem in terms of a graph, formulating fast sequential/parallel sub-optimal track detection algorithms and testing them on simulated data in order to show their detective ability. Moreover, we specify the conditions under which sub-optimal algorithms can perform at least as well as their corresponding optimal algorithms. This is significant for the track detection problem where fast, accurate and real-time detection is considered a necessity.  相似文献   
49.
This paper describes an efficient technique for the design of fault-secure VLSI circuits based on differential cascode voltage switch (DCVS) logic. We propose a new synthesis method for constructing DCVS circuits with a near-optimal transistor count based on binary decision diagrams (BDDs). the time and memory resources required are very low, making the technique practical even for PC-based synthesis tools. This method is the basis for a CAD tool that allows automatic synthesis of fault-secure circuits based on the DCVS technology. We finally present an improved design and implementation of a 2's complement serial/parallel multiplier as an application of the proposed technique and algorithm.  相似文献   
50.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号