全文获取类型
收费全文 | 734篇 |
免费 | 49篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 13篇 |
综合类 | 3篇 |
化学工业 | 207篇 |
金属工艺 | 31篇 |
机械仪表 | 38篇 |
建筑科学 | 21篇 |
矿业工程 | 3篇 |
能源动力 | 48篇 |
轻工业 | 54篇 |
水利工程 | 14篇 |
石油天然气 | 14篇 |
无线电 | 60篇 |
一般工业技术 | 131篇 |
冶金工业 | 33篇 |
原子能技术 | 3篇 |
自动化技术 | 120篇 |
出版年
2024年 | 1篇 |
2023年 | 14篇 |
2022年 | 22篇 |
2021年 | 35篇 |
2020年 | 49篇 |
2019年 | 59篇 |
2018年 | 79篇 |
2017年 | 42篇 |
2016年 | 52篇 |
2015年 | 34篇 |
2014年 | 52篇 |
2013年 | 79篇 |
2012年 | 60篇 |
2011年 | 64篇 |
2010年 | 46篇 |
2009年 | 32篇 |
2008年 | 20篇 |
2007年 | 10篇 |
2006年 | 16篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有793条查询结果,搜索用时 15 毫秒
1.
2.
This paper deals with a new boundary element method for analysis of the quasistatic problems in coupled thermoelasticity. Through some mathematical manipulation of the Navier equation in elasticity, the heat conduction equation is transformed into a simpler form, similar to the uncoupled-type equation with the modified thermal conductivity which shows the coupling effects. This procedure enables us to treat the coupled thermoelastic problems as an uncoupled one, A few examples are computed by the proposed BEM, and the results obtained are compared with the analytical ones available in the literature, whereby the accuracy and versatility of the proposed method are demonstrated. 相似文献
3.
4.
In this paper, a direct self‐structured adaptive fuzzy control is introduced for the class of nonlinear systems with unknown dynamic models. Control is accomplished by an adaptive fuzzy system with a fixed number of rules and adaptive membership functions. The reference signal and state errors are used to tune the membership functions and update them instantaneously. The Lyapunov synthesis method is also used to guarantee the stability of the closed loop system. The proposed control scheme is applied to an inverted pendulum and a magnetic levitation system, and its effectiveness is shown via simulation. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society 相似文献
5.
Tavakoli Rouhollah Mohseni Seyyed Mohammad 《Structural and Multidisciplinary Optimization》2014,49(4):621-642
Structural and Multidisciplinary Optimization - A new algorithm for the solution of multimaterial topology optimization problems is introduced in the present study. The presented method is based on... 相似文献
6.
Mehrdad Hakimi-Asiabar Seyyed Hassan Ghodsypour Reza Kerachian 《Applied Soft Computing》2010,10(4):1151-1163
Optimal multi-reservoir operation is a multi-objective problem in nature and some of its objectives are nonlinear, non-convex and multi-modal functions. There are a few areas of application of mathematical optimization models with a richer or more diverse history than in reservoir systems optimization. However, actual implementations remain limited or have not been sustained.Genetic Algorithms (GAs) are probabilistic search algorithms that are capable of solving a variety of complex multi-objective optimization problems, which may include non-linear, non-convex and multi-modal functions. GA is a population based global search method that can escape from local optima traps and find the global optima. However GAs have some drawbacks such as inaccuracy of the intensification process near the optimal set.In this paper, a new model called Self-Learning Genetic Algorithm (SLGA) is presented, which is an improved version of the SOM-Based Multi-Objective GA (SBMOGA) presented by Hakimi-Asiabar et al. (2009) [45]. The proposed model is used to derive optimal operating policies for a three-objective multi-reservoir system. SLGA is a new hybrid algorithm which uses Self-Organizing Map (SOM) and Variable Neighborhood Search (VNS) algorithms to add a memory to the GA and improve its local search accuracy. SOM is a neural network which is capable of learning and can improve the efficiency of data processing algorithms. The VNS algorithm can enhance the local search efficiency in the Evolutionary Algorithms (EAs).To evaluate the applicability and efficiency of the proposed methodology, it is used for developing optimal operating policies for the Karoon-Dez multi-reservoir system, which includes one-fifth of Iran's surface water resources. The objective functions of the problem are supplying water demands, generating hydropower energy and controlling water quality in downstream river. 相似文献
7.
8.
This study extends the literature on eating disorder symptomatology by testing, based on extant literature on objectification theory (B. L. Fredrickson & T. Roberts, 1997) and the role of sociocultural standards of beauty (e.g., L. J. Heinberg, J. K. Thompson, & S. Stormer, 1995), a model that examines (a) links of reported sexual objectification experiences to eating disorder-related variables and (b) the mediating roles of body surveillance, body shame, and internalization of sociocultural standards of beauty. Consistent with hypotheses, with a sample of 221 young women, support was found for a model in which (a) internalization of sociocultural standards of beauty mediated the links of sexual objectification experiences to body surveillance, body shame, and eating disorder symptoms, (b) body surveillance was an additional mediator of the link of reported sexual objectification experiences to body shame, and (c) body shame mediated the links of internalization and body surveillance to disordered eating. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Seyyed Ali Shojaee Mohammad Maleki Shahraki Mohammad Ali Faghihi Sani Ali Nemati Abbas Yousefi 《Journal of Materials Science: Materials in Electronics》2010,21(6):571-577
This paper describes a solution-based technique for fabrication of varistor grade composite nanopowders. The method consists
of coating major varistor dopants on the surface of the ZnO nanoparticles. As a result, a homogenous mixture of dopants and
ZnO nanoparticles will be achieved. TEM results indicated that a composite layer of dopants with the average particle size
of 9 nm on the surface of ZnO nanoparticles has been successfully prepared. Sintering of the coated powders was performed
in temperatures as low as 850 °C and final specimens with average particle size of 900 nm and density of 98.5% were achieved.
In comparison to conventional mixing, varistors prepared from coated nanopowders exhibited superior electrical properties
and microstructure homogeneity. The improvement of electrical properties can be attributed to small grain size, homogenous
distribution of dopants and elimination of large Bi-Pockets. In addition, the processing route of schottky barrier formation
is quite different from what is generally considered as the method of barrier formation in ZnO grain boundaries. 相似文献
10.
Yonghyun Jo Hanyoung Jang Yeon-Ho Kim Joon-Kee Cho Hadi Moradi 《Advanced Robotics》2013,27(4):301-308
This paper presents an octree-based map building algorithm for mobile home-service robots. The robot is equipped with a time-of-flight camera, which produces point clouds of the environment surfaces. Given the successive input of point clouds, a 3D map is incrementally computed in real time. The map is accurate and memory-efficient because the octree nodes containing points on a plane are merged and represented simply by an index to the plane. The real-time performance is achieved largely due to the parallel processing capability of the many-core Graphics Processing Unit used for plane extraction. 相似文献