全文获取类型
收费全文 | 1910篇 |
免费 | 108篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 26篇 |
综合类 | 2篇 |
化学工业 | 409篇 |
金属工艺 | 74篇 |
机械仪表 | 138篇 |
建筑科学 | 32篇 |
矿业工程 | 4篇 |
能源动力 | 84篇 |
轻工业 | 132篇 |
水利工程 | 13篇 |
石油天然气 | 4篇 |
武器工业 | 1篇 |
无线电 | 304篇 |
一般工业技术 | 394篇 |
冶金工业 | 116篇 |
原子能技术 | 21篇 |
自动化技术 | 271篇 |
出版年
2024年 | 1篇 |
2023年 | 38篇 |
2022年 | 38篇 |
2021年 | 79篇 |
2020年 | 55篇 |
2019年 | 77篇 |
2018年 | 60篇 |
2017年 | 62篇 |
2016年 | 79篇 |
2015年 | 54篇 |
2014年 | 117篇 |
2013年 | 147篇 |
2012年 | 142篇 |
2011年 | 153篇 |
2010年 | 100篇 |
2009年 | 101篇 |
2008年 | 97篇 |
2007年 | 98篇 |
2006年 | 78篇 |
2005年 | 50篇 |
2004年 | 53篇 |
2003年 | 45篇 |
2002年 | 21篇 |
2001年 | 39篇 |
2000年 | 23篇 |
1999年 | 25篇 |
1998年 | 43篇 |
1997年 | 24篇 |
1996年 | 19篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 16篇 |
1992年 | 12篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1977年 | 7篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1964年 | 1篇 |
1941年 | 1篇 |
排序方式: 共有2025条查询结果,搜索用时 31 毫秒
111.
112.
Sun Hwa Park Jin Gyeong Son Tae Geol Lee Hyun Min Park Jae Yong Song 《Nanoscale research letters》2013,8(1):248
We have synthesized micrometer-sized Ag nanosheets via a facile, one-step, template-free electrochemical deposition in an ultra-dilute silver nitrate aqueous electrolyte. The nanosheet growth was revealed to occur in three stages: (1) formation of polygonal Ag nuclei on a substrate, (2) growth of {112}-faceted nanowire from the nuclei, and (3) anisotropic growth of (111)-planar nanosheets, approximately 20 to 50 nm in thickness and 10 μm in width, in the <112>−direction. The vertical growth of the facet nanowire was induced by the strong interface anisotropy between the deposit and electrolyte due to the ultra-dilute concentration of electrolyte and high reduction potential. The thickness of Ag nanosheets was controllable by the adjustment of the reduction/oxidation potential and frequency of the reverse-pulse potentiodynamic mode. 相似文献
113.
114.
Yi-Joon Kim Sang-Un Lee Wa Gao Chung-Han Chung Chang-Woo Son Jin-Woo Lee 《Korean Journal of Chemical Engineering》2011,28(7):1580-1586
The optimal conditions of the downstream process for recovery of pullulan produced by Aureobasidium pullulans HP-2001 were examined using response surface method (RSM). The optimal amount of diatomite in filter press and the optimal
flow rate in a continuous flow centrifuge for removal of cells from the culture broth of A. pullulans HP-2001 were found to be 5.0% (v/v) and 2.0 L/min. Based on central composite design (CCD) experiments and analysis of variance
(ANOVA) indicated that the optimal conditions for recovery of pullulan from the supernatant by precipitation were the volume
ratio of ethanol (or isopropanol) to supernatant of 3.0: 1.0, the reaction time of 29.5 h, and the reaction temperature of
20.2 °C. The expected maximal recovery yields of pullulan using ethanol and isopropanol under optimized conditions were 79.2
and 85.5%, respectively. 相似文献
115.
It is a truism that today’s simulations of mobile wireless networks are not realistic. In realistic simulations of urban networks, the mobility of vehicles and pedestrians is greatly influenced by the environment (e.g., the location of buildings) as well as by interaction with other nodes. For example, on a congested street or sidewalk, nodes cannot travel at their desired speed. Furthermore, the location of streets, sidewalks, hallways, etc. restricts the position of nodes, and traffic lights impact the flow of nodes. And finally, people do not wander the simulated region at random, rather, their mobility depends on whether the person is at work, at lunch, etc. In this paper, realistic simulation of mobility for urban wireless networks is addressed. In contrast to most other mobility modeling efforts, most of the aspects of the presented mobility model and model parameters are derived from surveys from urban planning and traffic engineering research. The mobility model discussed here is part of the UDel Models, a suite of tools for realistic simulation of urban wireless networks. The UDel Models simulation tools are available online. 相似文献
116.
Real-time active database systems (RTADBSs) have attracted a considerable amount of research attention in the past and a number of important applications have been identified for such systems, such as telecommunications network management, automated air traffic control, automated financial trading, process control and military command and control systems. In spite of the recognized importance of this area, very little research has been devoted to exploring the dynamics of transaction processing in RTADBSs. Concurrency control (CC) constitutes an integral part of any transaction processing strategy and, thus, deserves special attention. We study CC strategies in RTADBSs and postulate a number of CC algorithms. These algorithms exploit the special needs and features of RTADBSs and are shown to deliver substantially superior performance to conventional real-time CC algorithms 相似文献
117.
Ryosuke Ueyama Masahiro Harada Tamotu Ueyama Takashi Yamamoto Tadashi Shiosaki Kiyoshi Kuribayashi Kunihito Koumoto Won Son Seo 《Journal of Materials Science: Materials in Electronics》2000,11(2):139-143
Ultrafine BaTiO3 particles were prepared by a micro-emulsion charring (MEC) method. The MEC method consisted of two steps. The first step is the preparation of a water/oil micro-emulsion with BaTiO3 elements, and the second is a low temperature firing process in N2 atmosphere, which includes charring of oil in an emulsion and powdering BaTiO3 particles with the char. The char formed around BaTiO3 particles prevents an agglomeration of BaTiO3 particles during firing. In the present experiment, the W/O ratio and the amount of emulsifier greatly influenced the size of droplets of the emulsion. The charring temperature was another important experimental factor in order to obtain the desired BaTiO3 particles. The finally obtained BaTiO3 charring powders were monodispersed spherical particles and the particle size was 0.1 m to 0.5 m. 相似文献
118.
Jinhui Cho Rakhwan Kim Kyoung-Woo Lee Choongyong Son Geun-Young Yeom Hee Jae Kim Jung-Yeul Kim Jong-Wan Park 《Journal of Materials Science》1999,34(20):5055-5059
The MgO-CaO composites films were prepared by e-beam evaporation to improve both operating voltages and memory coefficient of a protective layers for AC plasma display panels (PDPs). The effects of CaO addition to the conventional MgO films on both the electrical properties and the structural changes of the Mg1–xCaxO thin films deposited on the slide glass substrates were investigated. Atomic force microscopy (AFM) results revealed that the Mg0.8Ca0.2O film had a very rough surface due to the formation of a second phase on the surface. By adding controlled amount of CaO, the Mg-Ca-O films showed a firing voltage of 176 V that is lower than that of the conventional 100% MgO film. The deposition rates of 40–100 nm/min were obtained as a function of [CaO/(MgO+CaO)] ratio of the evaporation source materials. 相似文献
119.
This paper describes a novel method for heat-up phase control of an industrial batch polymerization reactor where heat transfer characteristics change with batches due to fouling of the polymer products on the reactor wall. The main objective of the control is to settle the reactor temperature on a target value within ± 0.1°C in a minimum possible time. To achieve this goal utilizing the repetitive nature of batch operation, the control problem was defined as a tracking problem and feedback-assisted iterative learning control (FBALC) was employed as the underlying control technique. The proposed control method was applied to an industrial batch reactor polymerizing ABS resin. After on-site evaluation for an extended period of time, it was found that the proposed method gives a pronounced improvement in heat-up phase operation. Consistent heat-up profiles with a minimized settling time are obtained. 相似文献
120.
Wookho Son Kyunghwan Kim Amato N.M. Trinkle J.C. 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2004,34(2):912-924
This paper presents a generalized framework for dynamic simulation realized in a prototype simulator called the Interactive Generalized Motion Simulator (I-GMS), which can simulate motions of multirigid-body systems with contact interaction in virtual environments. I-GMS is designed to meet two important goals: generality and interactivity. By generality, we mean a dynamic simulator which can easily support various systems of rigid bodies, ranging from a single free-flying rigid object to complex linkages such as those needed for robotic systems or human body simulation. To provide this generality, we have developed I-GMS in an object-oriented framework. The user interactivity is supported through a haptic interface for articulated bodies, introducing interactive dynamic simulation schemes. This user-interaction is achieved by performing push and pull operations via the PHANToM haptic device, which runs as an integrated part of I-GMS. Also, a hybrid scheme was used for simulating internal contacts (between bodies in the multirigid-body system) in the presence of friction, which could avoid the nonexistent solution problem often faced when solving contact problems with Coulomb friction. In our hybrid scheme, two impulse-based methods are exploited so that different methods are applied adaptively, depending on whether the current contact situation is characterized as "bouncing" or "steady." We demonstrate the user-interaction capability of I-GMS through on-line editing of trajectories of a 6-degree of freedom (dof) articulated structure. 相似文献