首页 | 官方网站   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   942篇
  免费   32篇
  国内免费   5篇
工业技术   979篇
  2024年   1篇
  2023年   4篇
  2022年   14篇
  2021年   24篇
  2020年   16篇
  2019年   13篇
  2018年   20篇
  2017年   24篇
  2016年   27篇
  2015年   25篇
  2014年   34篇
  2013年   53篇
  2012年   40篇
  2011年   50篇
  2010年   34篇
  2009年   52篇
  2008年   40篇
  2007年   37篇
  2006年   45篇
  2005年   30篇
  2004年   23篇
  2003年   33篇
  2002年   32篇
  2001年   29篇
  2000年   16篇
  1999年   18篇
  1998年   42篇
  1997年   34篇
  1996年   32篇
  1995年   19篇
  1994年   9篇
  1993年   9篇
  1992年   9篇
  1991年   11篇
  1990年   10篇
  1989年   7篇
  1988年   7篇
  1987年   8篇
  1986年   6篇
  1985年   8篇
  1984年   8篇
  1983年   3篇
  1982年   7篇
  1981年   3篇
  1980年   2篇
  1979年   1篇
  1977年   5篇
  1976年   3篇
  1973年   1篇
  1972年   1篇
排序方式: 共有979条查询结果,搜索用时 15 毫秒
1.
In addition to satisfying several competing objectives, many real-world applications are also characterized by a certain degree of noise, manifesting itself in the form of signal distortion or uncertain information. In this paper, extensive studies are carried out to examine the impact of noisy environments in evolutionary multiobjective optimization. Three noise-handling features are then proposed based upon the analysis of empirical results, including an experiential learning directed perturbation operator that adapts the magnitude and direction of variation according to past experiences for fast convergence, a gene adaptation selection strategy that helps the evolutionary search in escaping from local optima or premature convergence, and a possibilistic archiving model based on the concept of possibility and necessity measures to deal with problem of uncertainties. In addition, the performances of various multiobjective evolutionary algorithms in noisy environments, as well as the robustness and effectiveness of the proposed features are examined based upon five benchmark problems characterized by different difficulties in local optimality, nonuniformity, discontinuity, and nonconvexity  相似文献   
2.
3.
The excavation of soil for the construction of basements or cut-and-cover tunnels results in ground movements. One particular concern is that the excavation-induced lateral soil movements may adversely affect any nearby pile foundation. The lateral loads imposed by the soil movements induce bending moments and deflections in the pile, which may lead to structural distress and failure. This paper presents the results of an actual full-scale instrumented study that was carried to examine the behavior of an existing pile due to nearby excavation activities resulting from the construction of a 16 m deep cut-and-cover tunnel. The pile was located 3 m behind a 0.8 m thick diaphragm wall. Excavation to the formation level that was 16 m below the ground surface resulted in a maximum lateral pile movement of 28 mm. A simplified numerical procedure based on the finite-element method was used to analyze the pile response. Generally, the theoretical predictions were in reasonable agreement with the measured results.  相似文献   
4.
5.
We report a dispersion slope equalizer on a planar lightwave circuit for wavelength division multiplexing (WDM) transmission. This device consists of an array of lattice-formed equalizers with different compensation values fabricated on one wafer and arrayed-waveguide gratings for wavelength multi/demultiplexing. We describe its configuration, operational principle, parameter design, fabrication, and measured characteristics in detail. N/spl times/20 and N/spl times/40 Gb/s slope equalizers were fabricated and their characteristics agreed well with designed values. We also report a reduction in the bias electrical power needed for thermooptic phase shifters in the equalizer array that we realized by employing a phase trimming technique normally used for optical switches.  相似文献   
6.
Cntextual logic provides a mechanism to reason about modules.In this paper,this theory of modules if modules is extended to a context theory of classes where class is in the true spirit of object-oriented databases.The logic,referred to as CLOG,is class-based.CLOG supports class,object identity,multiple role of object, monotonic and non-monotonic inheritance of data and method,method factoring,views,derived and query classes.Views and derived classes are queries in themselves.Objects are pure data terms representing the ground instances of facts in the class.Object identity is a first class term in the logic.Inheritance is handled through delegation.  相似文献   
7.
Abstract— In this paper, a software‐processed edge‐ and level‐adaptive overdrive (SELAO) method, which is a novel overdrive technique that utilizes not only a temporal change of gray levels but also a spatial edge intensity of motion pictures, is proposed. The SELAO method is a software video‐processing technology to improve motion‐picture quality rendered on LCDs more than is possible with a conventional SLAO method without edge‐adaptive overdrive, and it works in real time on commonly used personal computers (PCs).  相似文献   
8.
Poly(tetrahydropyranyl-2-methacrylate) (PTHPMA) was found to be miscible with Poly(vinyl phenol) (PVPH), Poly(hydroxy ether of bisphenol A) (Phenoxy), and Poly(styrene-co-allyl alcohol) (PSAA). However, Poly(cyclohexyl methacrylate) (PCHMA) is immiscible with all these three hydroxyl-containing polymers. Poly(acetonyl methacrylate) (PACMA) was found to be miscible with PVPH but immiscible with Phenoxy and PSAA. Miscible PTHPMA-Phenoxy blends showed lower critical solution temperature behavior.  相似文献   
9.
We address the computational resource requirements of 3D example-based synthesis with an adaptive synthesis technique that uses a tree-based synthesis map. A signed-distance field (SDF) is determined for the 3D exemplars, and then new models can be synthesized as SDFs by neighborhood matching. Unlike voxel synthesis approach, our input is posed in the real domain to preserve maximum detail. In comparison to straightforward extensions to the existing volume texture synthesis approach, we made several improvements in terms of memory requirements, computation times, and synthesis quality. The inherent parallelism in this method makes it suitable for a multicore CPU. Results show that computation times and memory requirements are very much reduced, and large synthesized scenes exhibit fine details which mimic the exemplars.  相似文献   
10.
Ionic conductivity of the Ag2O-MoO3-V205 system has been studied over a wide range of frequency, temperature and composition. A narrower glass forming region has been found in comparison to the corresponding Ag2O-MoO3-P2O5 and Ag2O-B2O3-P2O5 systems. The highest conductivity at room temperature, rt, = 3.21 × 10–6–1 cm–1 (d.c.) with an activation energy,E act, of 0.466 eV, was observed for the glass former's ratio of unity. Further, it reached a maximum value of 2.2 × 10–2¨-1 cm–1 withE act = 0.153 eV when the oxide-base glass was dissolved with Agl. D.c. conductivity, hopping rate and relaxation time in the present system have been found to be characterized by the same activation energy.  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-23

京公网安备 11010802026262号