全文获取类型
收费全文 | 11208篇 |
免费 | 586篇 |
国内免费 | 301篇 |
专业分类
电工技术 | 731篇 |
综合类 | 488篇 |
化学工业 | 1503篇 |
金属工艺 | 497篇 |
机械仪表 | 419篇 |
建筑科学 | 365篇 |
矿业工程 | 242篇 |
能源动力 | 324篇 |
轻工业 | 845篇 |
水利工程 | 184篇 |
石油天然气 | 142篇 |
武器工业 | 103篇 |
无线电 | 1073篇 |
一般工业技术 | 1417篇 |
冶金工业 | 2694篇 |
原子能技术 | 167篇 |
自动化技术 | 901篇 |
出版年
2024年 | 38篇 |
2023年 | 117篇 |
2022年 | 242篇 |
2021年 | 367篇 |
2020年 | 208篇 |
2019年 | 151篇 |
2018年 | 196篇 |
2017年 | 206篇 |
2016年 | 173篇 |
2015年 | 240篇 |
2014年 | 304篇 |
2013年 | 481篇 |
2012年 | 520篇 |
2011年 | 629篇 |
2010年 | 506篇 |
2009年 | 531篇 |
2008年 | 513篇 |
2007年 | 516篇 |
2006年 | 482篇 |
2005年 | 378篇 |
2004年 | 328篇 |
2003年 | 253篇 |
2002年 | 259篇 |
2001年 | 219篇 |
2000年 | 184篇 |
1999年 | 195篇 |
1998年 | 880篇 |
1997年 | 531篇 |
1996年 | 378篇 |
1995年 | 260篇 |
1994年 | 248篇 |
1993年 | 216篇 |
1992年 | 101篇 |
1991年 | 103篇 |
1990年 | 100篇 |
1989年 | 86篇 |
1988年 | 86篇 |
1987年 | 63篇 |
1986年 | 79篇 |
1985年 | 91篇 |
1984年 | 52篇 |
1983年 | 59篇 |
1982年 | 50篇 |
1981年 | 63篇 |
1980年 | 61篇 |
1979年 | 30篇 |
1978年 | 28篇 |
1977年 | 81篇 |
1976年 | 116篇 |
1975年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
141.
We propose a quantum bit-commitment scheme based on quantum one-way permutations with the unconditionally binding and computationally
concealing property. Our scheme reduces exponentially the number of bits which the receiver needs to store until, the opening
phase compared with the classical counterpart.
Keisuke Tanaka, Ph.D.: He is Assistant Professor of Department of Mathematical and Computing Sciences at Tokyo Institute of Technology. He received
his B.S. from Yamanashi University in 1992 and his M.S. and Ph.D. from Japan Advanced Institute of Science and Technology
in 1994 and 1997, respectively. For each degree, he majored in computer science. Before joining Tokyo Institute of Technology,
he was Research Engineer at NTT Information Sharing Platform Laboratories. His research interests are cryptography, quantum
computation, circuit complexity, and the design and analysis of algorithms. 相似文献
142.
一种新型单总线数字温度传感器的特性与应用 总被引:7,自引:0,他引:7
介绍了新型单总线数字温度传感器DS18B20的特性,外部封装和内部结构,描述了DS18B20和单片机的硬件连接和软件编程,并给出了一种实际的应用。 相似文献
143.
144.
非完整自主车基于圆轨迹的道路避障 总被引:2,自引:0,他引:2
本文就四轮非完整自主车提出了一种基于圆轨迹的道路避障策略.先将道路上
的障碍按照障碍距离自主车的远近划分层次,使一个层次的障碍能在自主车视场中全部出现
.然后给出基于圆轨迹的避障算法,即自主车沿由自主车出发位姿和子目标点确定的圆弧轨
迹走行.在此之前推导四轮非完整车的运动模型为提出避障策略的基础准备.尽量减小自主
车在走行过程中运动状态的改变,基于圆轨迹避障策略能够很好地满足这一要求.最后引入
代价函数,给出对于此方法的评价,体现了本方法的优越性. 相似文献
145.
Neuro-fuzzy control of a robotic exoskeleton with EMG signals 总被引:1,自引:0,他引:1
We have been developing robotic exoskeletons to assist motion of physically weak persons such as elderly, disabled, and injured persons. The robotic exoskeleton is controlled basically based on the electromyogram (EMG) signals, since the EMG signals of human muscles are important signals to understand how the user intends to move. Even though the EMG signals contain very important information, however, it is not very easy to predict the user's upper-limb motion (elbow and shoulder motion) based on the EMG signals in real-time because of the difficulty in using the EMG signals as the controller input signals. In this paper, we propose a robotic exoskeleton for human upper-limb motion assist, a hierarchical neuro-fuzzy controller for the robotic exoskeleton, and its adaptation method. 相似文献
146.
Surface degradation of polyamide nanocomposites caused by partial discharges using IEC (b) electrodes 总被引:1,自引:0,他引:1
Kozako M. Fuse N. Ohki Y. Okamoto T. Tanaka T. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2004,11(5):833-839
Partial discharge (PD) degradation of polyamide both without nanoscale fillers (nanofillers) and with 2,4 and 5 wt% additions of nanofillers was investigated. Such materials were subjected to PDs using the IEC (b) electrodes for evaluation. Comparisons were made as to the surface roughness observed by scanning electron microscopy and atomic force microscopy. It was found that the change in the surface roughness is far smaller in specimens with nanofillers than those without nanofillers, and that the 2 wt% addition is sufficient for improvement of the surface roughness. Furthermore, it was elucidated that the difference of surface roughness of the degraded area due to PDs among the specimens originates from the difference in their crystalline structures. These results indicate that polyamide nanocomposite is more resistance to PDs than polyamide without nanofillers. 相似文献
147.
Jianming Zhang Masataka Tanaka Toshiro Matsumoto 《International journal for numerical methods in engineering》2004,59(9):1147-1166
Combining a modified functional with the moving least‐squares (MLS) approximation, the hybrid boundary node method (Hybrid BNM) is a truly meshless, boundary‐only method. The method may have advantages from the meshless local boundary integral equation (MLBIE) method and also the boundary node method (BNM). In fact, the Hybrid BNN requires only the discrete nodes located on the surface of the domain. The Hybrid BNM has been applied to solve 2D potential problems. In this paper, the Hybrid BNM is extended to solve potential problems in three dimensions. Formulations of the Hybrid BNM for 3D potential problems and the MLS approximation on a generic surface are developed. A general computer code of the Hybrid BNM is implemented in C++. The main drawback of the ‘boundary layer effect’ in the Hybrid BNM in the 2D case is circumvented by an adaptive face integration scheme. The parameters that influence the performance of this method are studied through three different geometries and known analytical fields. Numerical results for the solution of the 3D Laplace's equation show that high convergence rates with mesh refinement and high accuracy are achievable. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
148.
A. Korematsu T. Furuzono S. Yasuda J. Tanaka A. Kishida 《Journal of Materials Science》2004,39(9):3221-3225
149.
以黄泛平原壤质潮土不同年限的设施栽培土壤为研究对象,探讨了设施栽培条件对土壤养分及土壤有机质组成的影响。结果表明,设施栽培土壤碱解氮、速效磷、速效钾、盐分含量均明显高于大田,其含量主要取决于施用化学肥料的种类和数量,随栽培年限的增加而增加;土壤有机质、腐殖酸、胡敏酸含量随种植年限有升高趋势;HA/FA与栽培年限显著相关,表示设施栽培条件下,土壤熟化程度随有机肥料的逐年施用而有所提高,但HA/FA变化幅度不大,这可能与设施栽培形成的高温高湿条件及施用有机肥料中难分解物质的含量有关。 相似文献
150.
Masaji Tanaka Author Vitae Laurence Anthony Author Vitae Toshiaki Kaneeda Author Vitae Junji Hirooka Author Vitae 《Computer aided design》2004,36(8):723-734
Although solid models play a central role in modern CAD systems, 2D CAD systems are still commonly used for designing products without complex curved faces. Therefore, an important task is to convert 2D drawings to solid models, and this is usually carried out manually even in present CAD systems. Many methods have been proposed to automatically convert orthographic part drawings of solid objects to solid models. Unfortunately, products are usually drawn as 2D assembly drawings, and therefore, these methods cannot be applied. A further problem is the difficult and time-consuming task of decomposing 2D assembly drawings into 2D part drawings. In previous work, the authors proposed a method to automatically decompose 2D assembly drawings into 3D part drawings, from which 2D part drawings can be easily generated. However, one problem with the proposed method was that the number of solutions could easily explode if the 2D assembly drawings became complex. Building on this work, here we describe a new method to automatically convert 2D assembly drawings to 3D part drawings, generating a unique solution for designers regardless of the complexity of the original 2D assembly drawings. The only requirement for the approach is that the assembly drawings consist of standard parts such as bars and plates. In 2D assembly drawings, the dimensions, part numbers and parts lists are usually drawn, and the proposed method utilizes these to obtain a unique solution. 相似文献