全文获取类型
收费全文 | 2522篇 |
免费 | 164篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 22篇 |
综合类 | 2篇 |
化学工业 | 645篇 |
金属工艺 | 130篇 |
机械仪表 | 176篇 |
建筑科学 | 42篇 |
能源动力 | 150篇 |
轻工业 | 209篇 |
水利工程 | 21篇 |
石油天然气 | 5篇 |
武器工业 | 2篇 |
无线电 | 349篇 |
一般工业技术 | 498篇 |
冶金工业 | 113篇 |
原子能技术 | 54篇 |
自动化技术 | 273篇 |
出版年
2024年 | 3篇 |
2023年 | 34篇 |
2022年 | 65篇 |
2021年 | 100篇 |
2020年 | 62篇 |
2019年 | 63篇 |
2018年 | 83篇 |
2017年 | 83篇 |
2016年 | 85篇 |
2015年 | 78篇 |
2014年 | 119篇 |
2013年 | 171篇 |
2012年 | 227篇 |
2011年 | 252篇 |
2010年 | 161篇 |
2009年 | 181篇 |
2008年 | 134篇 |
2007年 | 91篇 |
2006年 | 100篇 |
2005年 | 87篇 |
2004年 | 70篇 |
2003年 | 62篇 |
2002年 | 53篇 |
2001年 | 58篇 |
2000年 | 55篇 |
1999年 | 41篇 |
1998年 | 65篇 |
1997年 | 25篇 |
1996年 | 15篇 |
1995年 | 12篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有2691条查询结果,搜索用时 15 毫秒
31.
Bae Jun Young 《Information Sciences》2009,179(24):4284-1770
The idea of (faithful) intuitionistic fuzzy transformation semigroup, intuitionistic admissible relation, and intuitionistic (strong) homomorphism are introduced and their basic properties are examined. 相似文献
32.
Sanghoon Park Roxana Shabani Mark Schumacher Yoon-Seoung Kim Young Min Bae Kyeong-Hee Lee Hyoung Jin Cho 《Microsystem Technologies》2016,22(8):2077-2085
Miniaturized on-chip blood separators have a great value for point-of-care diagnosis. In our work, a combined design strategy—microfiltration, sedimentation in a retarded flow, and wetting contrast—was taken to overcome the known limitations of on-chip blood separators. Our microfluidic chip consists of a polydimethylsiloxane micropillar array and an etched glass with microchannel branches. The red blood cells are significantly slowed and gradually settled down due to micropillars and enlarged dimension of a chamber. An etched glass microchannel allows the extraction of blood plasma exclusively due to the capillary effect. The fabricated microfluidic device can separate blood plasma from a whole blood sample without any external driving force or dilution. The measured plasma separation efficiency was close to 100 % from human whole blood. Autonomous on-chip separation and collection of blood plasma was demonstrated. 相似文献
33.
This paper provides simple and effective linear matrix inequality (LMI) characterizations for the stability and stabilization conditions of discrete-time Takagi–Sugeno (T–S) fuzzy systems. To do this, more general classes of non-parallel distributed compensation (non-PDC) control laws and non-quadratic Lyapunov functions are presented. Unlike the conventional non-quadratic approaches using only current-time normalized fuzzy weighting functions, we consider not only the current-time fuzzy weighting functions but also the l-step-past (l?0) and one-step-ahead ones when constructing the control laws and Lyapunov functions. Consequently, by introducing additional decision variables, it can be shown that the proposed conditions include the existing ones found in the literature as particular cases. Examples are given to demonstrate the effectiveness of the approaches. 相似文献
34.
Petri net is used widely to analyze and model various systems formally. Recently, many Petri nets mania devote their efforts to enhancing and extending the expressive power of Petri nets. One such effort is to extend Petri nets with object-oriented concepts. An object-oriented paradigm provides excellent concepts to model real-world problems. Object-oriented concepts allow us to build software systems easily, intuitively, and naturally. Although several high-level Petri nets with the concept of objects are suggested, these nets do not fully support the object-oriented concepts. In this paper, we propose a hierarchical object-oriented Petri net (HOONet). The formal syntax and semantics of HOONet are explained in detail. HOONet supports a wide range of object-oriented features including abstract, encapsulated and modularized objects, object interaction by message passing, inheritance, and ploymorphism. HOONet also supports a variety of modeling and analysis mechanisms such as incremental modeling of evolving systems, unfolding the HOONet to lower level Petri net, and incremental reachability analysis for HOONet models. We demonstrate the usefulness of HOONet by applying it to modeling and analysis with an example. 相似文献
35.
Adaptive Output Feedback Control of Flexible-Joint Robots Using Neural Networks: Dynamic Surface Design Approach 总被引:1,自引:0,他引:1
Sung Jin Yoo Jin Bae Park Yoon Ho Choi 《Neural Networks, IEEE Transactions on》2008,19(10):1712-1726
In this paper, we propose a new robust output feedback control approach for flexible-joint electrically driven (FJED) robots via the observer dynamic surface design technique. The proposed method only requires position measurements of the FJED robots. To estimate the link and actuator velocity information of the FJED robots with model uncertainties, we develop an adaptive observer using self-recurrent wavelet neural networks (SRWNNs). The SRWNNs are used to approximate model uncertainties in both robot (link) dynamics and actuator dynamics, and all their weights are trained online. Based on the designed observer, the link position tracking controller using the estimated states is induced from the dynamic surface design procedure. Therefore, the proposed controller can be designed more simply than the observer backstepping controller. From the Lyapunov stability analysis, it is shown that all signals in a closed-loop adaptive system are uniformly ultimately bounded. Finally, the simulation results on a three-link FJED robot are presented to validate the good position tracking performance and robustness of the proposed control system against payload uncertainties and external disturbances. 相似文献
36.
Indicating that CBMC does not satisfy the monotonic property in terms of the number of interactions, Xu and Zhou proposed an augmented definition of CBMC by adopting cut set instead of glue methods. The augmented CBMC clearly satisfies the monotonic property. However, CBMC is designed to overcome the problem with respect to the number of interactions and, therefore, focuses on the interaction pattern, especially, member connectivity. Consequently, it does not make sense to mention the monotonic property of CBMC with respect to interaction number. Moreover, the notion of glue methods allows several interpretations on the design quality of a class. However, that meaningful interpretation is not possible for the augmented definition due to the removal of the notion of glue methods. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
37.
Forced internal waves at the interface of a two-layer incompressible fluid in a two-dimensional domain with rigid horizontal boundaries are studied. The lower boundary is assumed to have a small obstruction. We derive a time-dependent forced modified KdV equation when the KdV theory fails and study the stabilities of four types of symmetric time-independent solitary-wave-like solutions numerically. 相似文献
38.
By means of a kind of new idea, we redefine fuzzy ideals and fuzzy interior ideals in a $\Upgamma$ -ring and investigate some of their related properties. In particular, we show that the regular and semisimple $\Upgamma$ -rings can be described by using these kinds of generalized fuzzy ideals. 相似文献
39.
This paper presents an integrated framework for risk evaluation and risk allocation with bounded data in a critical risk management. A risk evaluation framework using the Imprecise Data Envelopment Analysis (IDEA) method is proposed to be applied to operations of Korean Army helicopters. The risks pertaining to pilots, missions and helicopters are evaluated based on bounded data, and pilots are appropriately allocated to missions and helicopters using goal programming with bounded risk scores. Using bounded data, two risk allocation models are developed to be used with the expected value and lower/upper limit values, resulting in improved reliability of the solutions. Numerical experiments show reasonable solutions and valuable information for risk management. 相似文献
40.
Kee Bae Park Sang-Do Han Il Jin Kim Jin Suk Wang Young Sung Park 《Materials Science and Engineering: B》2006,130(1-3):158-162
Thick film H2 sensors were fabricated using SnO2 loaded with Ag2O and PdOx. The composition that gave highest sensitivity for H2 was in the wt.% ratio of SnO2:Ag2O:PdOx as 93:5:2. The nano-crystalline powders of SnO2–Ag2O–PdOx composites synthesized by sol–gel method were screen printed on alumina substrates. Fabricated sensors were tested against gases like H2, CH4, C3H8, C2H5OH and SO2. The composite material was found sensitive against H2 at the working temperature 125 °C, with minor interference of other gases. H2 gas as low as 100 ppm can be detected by the present fabricated sensors. It was found that the sensors based on SnO2–Ag2O–PdOx nanocrystalline system exhibited high performance, high selectivity and very short response time to H2 at ppm level. These characteristics make the sensor to be a promising candidate for detecting low concentrations of H2. 相似文献