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   1252篇
  免费   35篇
  国内免费   2篇
电工技术   44篇
综合类   3篇
化学工业   197篇
金属工艺   57篇
机械仪表   21篇
建筑科学   76篇
矿业工程   9篇
能源动力   63篇
轻工业   92篇
水利工程   16篇
石油天然气   4篇
无线电   114篇
一般工业技术   208篇
冶金工业   169篇
原子能技术   10篇
自动化技术   206篇
  2024年   4篇
  2023年   6篇
  2022年   9篇
  2021年   13篇
  2020年   8篇
  2019年   22篇
  2018年   22篇
  2017年   24篇
  2016年   27篇
  2015年   23篇
  2014年   26篇
  2013年   75篇
  2012年   62篇
  2011年   83篇
  2010年   73篇
  2009年   63篇
  2008年   124篇
  2007年   96篇
  2006年   74篇
  2005年   87篇
  2004年   52篇
  2003年   37篇
  2002年   45篇
  2001年   25篇
  2000年   9篇
  1999年   19篇
  1998年   16篇
  1997年   18篇
  1996年   19篇
  1995年   19篇
  1994年   13篇
  1993年   7篇
  1992年   12篇
  1991年   3篇
  1990年   6篇
  1989年   5篇
  1988年   15篇
  1987年   5篇
  1986年   7篇
  1985年   5篇
  1984年   10篇
  1983年   5篇
  1982年   2篇
  1981年   2篇
  1980年   2篇
  1979年   3篇
  1976年   2篇
  1975年   3篇
  1972年   1篇
  1947年   1篇
排序方式: 共有1289条查询结果,搜索用时 375 毫秒
31.
Hume is a contemporary programming language oriented to systems with strong resource bounds, based on autonomous concurrent “boxes” interacting across “wires”. Hume’s design reflects the explicit separation of coordination and computation aspects of multi-process systems, which greatly eases establishing resource bounds for programs. However, coordination and computation are necessarily tightly coupled in reasoning about Hume programs. Furthermore, in Hume, local changes to coordination or computation, while preserving input/output correctness, can have profound and unforeseen effects on other aspects of programs such as timing of events and scheduling of processes. Thus, traditional program calculi prove inappropriate as they tend to focus exclusively either on the coordination of interacting processes or on computation within individual processes.  相似文献   
32.
We introduce Process Overview, a situation awareness characterisation of the knowledge derived from monitoring process plants. Process Overview is based on observational studies of process control work in the literature. The characterisation is applied to develop a query-based measure called the Process Overview Measure. The goal of the measure is to improve coupling between situation and awareness according to process plant properties and operator cognitive work. A companion article presents the empirical evaluation of the Process Overview Measure in a realistic process control setting. The Process Overview Measure demonstrated sensitivity and validity by revealing significant effects of experimental manipulations that corroborated with other empirical results. The measure also demonstrated adequate inter-rater reliability and practicality for measuring SA based on data collected by process experts.

Practitioner Summary: The Process Overview Measure is a query-based measure for assessing operator situation awareness from monitoring process plants in representative settings.  相似文献   

33.
In a buyer-supplier game, a special type of assignment game, a distinguished player, called the buyer, wishes to purchase some combinatorial structure. A set of players, called suppliers, offer various components of the structure for sale. Any combinatorial minimization problem can be transformed into a buyer-supplier game. While most previous work has been concerned with characterizing the core of buyer-supplier games, in this paper we study optimization over the set of core vectors. We give a polynomial time algorithm for optimizing over the core of any buyer-supplier game for which the underlying minimization problem is solvable in polynomial time. In addition, we show that it is hard to determine whether a given vector belongs to the core if the base minimization problem is not solvable in polynomial time. Finally, we introduce and study the concept of focus point price, which answers the question: If we are constrained to play in equilibrium, how much can we lose by playing the wrong equilibrium?  相似文献   
34.
Laser-induced fluorescence (LIF) measurements have been performed for the first time in a low temperature (Te approximately 0.6 eV) Xe plasma using a tunable diode laser in the visible range of wavelengths. The transition in Xe II involved the (3P1)5d[3]7/2 metastable state and the excitation wavelength was found to be 680.570+/-0.001 nm (air). LIF measurements of I 2 in a room temperature iodine gas cell were used to monitor the wavelength of the laser during the measurements.  相似文献   
35.
This paper addresses the problem of calibrating camera parameters using variational methods. One problem addressed is the severe lens distortion in low-cost cameras. For many computer vision algorithms aiming at reconstructing reliable representations of 3D scenes, the camera distortion effects will lead to inaccurate 3D reconstructions and geometrical measurements if not accounted for. A second problem is the color calibration problem caused by variations in camera responses that result in different color measurements and affects the algorithms that depend on these measurements. We also address the extrinsic camera calibration that estimates relative poses and orientations of multiple cameras in the system and the intrinsic camera calibration that estimates focal lengths and the skew parameters of the cameras. To address these calibration problems, we present multiview stereo techniques based on variational methods that utilize partial and ordinary differential equations. Our approach can also be considered as a coordinated refinement of camera calibration parameters. To reduce computational complexity of such algorithms, we utilize prior knowledge on the calibration object, making a piecewise smooth surface assumption, and evolve the pose, orientation, and scale parameters of such a 3D model object without requiring a 2D feature extraction from camera views. We derive the evolution equations for the distortion coefficients, the color calibration parameters, the extrinsic and intrinsic parameters of the cameras, and present experimental results.  相似文献   
36.
A Logic of Access Control   总被引:2,自引:0,他引:2  
  相似文献   
37.
38.
We studied the methyltrioxorhenium (MTO)-CH2Cl2/H2O2 biphasic system for epoxidizing soybean oil. The reactions were optimized (reactant ratio, time, and temperature), which resulted in a better performance (higher conversion and selectivity) than those described in the literature. Total doublebond conversion and 95% selectivity were obtained in 2 h at room temperature. Furthermore, it was possible to reach desired epoxidation degrees by changing the oxidant and MTO amounts. The rhenium-epoxidized soybean oil remained stable in the absence of stabilizers for up to 30 d when stored at mild conditions.  相似文献   
39.
40.
当前采用软件服务供应商(ASP)之风再度复苏显然是事出有因:软件获取成本降低——通过取消购买和管理服务器硬件、操作系统、存储设备和其他一些支持设施,ASP托管能够减少50%,甚至更多的软件生命周期所有权成本。  相似文献   
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