全文获取类型
收费全文 | 13532篇 |
免费 | 1200篇 |
国内免费 | 474篇 |
专业分类
电工技术 | 575篇 |
综合类 | 444篇 |
化学工业 | 2531篇 |
金属工艺 | 609篇 |
机械仪表 | 519篇 |
建筑科学 | 729篇 |
矿业工程 | 271篇 |
能源动力 | 447篇 |
轻工业 | 1082篇 |
水利工程 | 212篇 |
石油天然气 | 313篇 |
武器工业 | 64篇 |
无线电 | 2261篇 |
一般工业技术 | 2176篇 |
冶金工业 | 858篇 |
原子能技术 | 110篇 |
自动化技术 | 2005篇 |
出版年
2024年 | 50篇 |
2023年 | 236篇 |
2022年 | 437篇 |
2021年 | 648篇 |
2020年 | 505篇 |
2019年 | 445篇 |
2018年 | 505篇 |
2017年 | 501篇 |
2016年 | 602篇 |
2015年 | 536篇 |
2014年 | 673篇 |
2013年 | 1001篇 |
2012年 | 822篇 |
2011年 | 898篇 |
2010年 | 733篇 |
2009年 | 721篇 |
2008年 | 681篇 |
2007年 | 615篇 |
2006年 | 580篇 |
2005年 | 523篇 |
2004年 | 363篇 |
2003年 | 332篇 |
2002年 | 292篇 |
2001年 | 260篇 |
2000年 | 228篇 |
1999年 | 222篇 |
1998年 | 341篇 |
1997年 | 217篇 |
1996年 | 176篇 |
1995年 | 157篇 |
1994年 | 115篇 |
1993年 | 137篇 |
1992年 | 68篇 |
1991年 | 82篇 |
1990年 | 50篇 |
1989年 | 57篇 |
1988年 | 46篇 |
1987年 | 31篇 |
1986年 | 31篇 |
1985年 | 32篇 |
1984年 | 41篇 |
1983年 | 21篇 |
1982年 | 25篇 |
1981年 | 24篇 |
1980年 | 22篇 |
1979年 | 18篇 |
1978年 | 18篇 |
1977年 | 19篇 |
1974年 | 8篇 |
1973年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
提出了一种识别方形QAM信号(4QAM、16QAM、64QAM和256QAM)的新方法,该方法将特征参数和信号降阶算法有效的结合.所选用的特征参数提取简单且易于实现,不受加性高斯噪声的影响;给出了该算法的理论推导,计算机仿真也表明该参数对滚降系数不敏感;选用的降阶方法不受载波相位的影响,较为实用.实验结果表明,该识别方法能够有效的识别方形QAM信号,4QAM、16QAM、64QAM和256QAM的识别率达到80%以上所需的信噪比分别为9dB、15dB、24dB和24dB. 相似文献
92.
UML代表着软件建模的发展趋势,对基于UML模型的测试技术研究具有现实意义。本文采用基于UML模型的场景测试技术生成测试用例。 相似文献
93.
在分析了实现手机人机界面(MMI)软件自动化测试的原理和技术难点的基础上,通过游程长度编码算法对屏幕数据进行压缩和一些数据比较技巧来解决屏幕数据传输与比较问题;通过一系列容错处理来保证ATS系统在无人参与的情况下自动运行;通过对系统软硬件进行抽象和加入TCL脚本解释器来增强系统的可扩展性和可重用性;最后应用这些技术方案实现了一个实际可用的ATS系统;应用结果表明,该系统能大幅提高手机MMI的测试效率。 相似文献
94.
Hyun‐Sang Park Seon‐Beom Ji Min‐Koo Han Jae‐Sic Lee Chi‐Woo Kim Kwang‐Soo Choi 《Journal of the Society for Information Display》2009,17(8):681-686
Abstract— A new digital ambient‐light sensor system is presented which employs two linear light sensors with different sensitivities and automatically adjusts the sensitivity based on the illumination condition. The adaptation mechanism allows a very wide range of light intensity to be detected, and the input dynamic range of the system is substantially improved from 22.5 to 45.1 dB. The proposed method does not require any additional precision bits for output data. Due to the small number of the output bits and the simple conversion process, the system can be easily integrated on the display panel. 相似文献
95.
Bensalem S. Gallien M. Ingrand F. Kahloul I. Nguyen Thanh-Hung 《Robotics & Automation Magazine, IEEE》2009,16(1):67-77
Autonomous robots are complex systems that require the interaction or cooperation of numerous heterogeneous software components. Nowadays, robots are getting closer to humans and as such are becoming critical systems that must meet safety properties including logical, temporal, and real-time constraints. 相似文献
96.
This paper presents theoretical and experimental investigations on electroosmotic control of stream width in hydrodynamic
focusing. In the experiments, three liquids (aqueous NaCl, aqueous glycerol and aqueous NaCl) are introduced by syringe pumps
to flow side by side in a straight rectangular microchannel. External electric fields are applied on the two aqueous NaCl
streams. Under the same inlet volumetric flow rates, the applied electric fields are varied to control the interface positions
and consequently the width of the focused aqueous glycerol stream. The electroosmotic effect on the width of the aqueous glycerol
is measured using fluorescence imaging technique. The electroosmotic effect under different flow rates, different viscosity,
and aspect ratio are investigated. The results indicate that the electroosmotic effect on the pressure-driven flow becomes
weaker with the increase in flow rates, viscosity ratio or aspect ratio of the channel. The measured results of the focused
width of the non-conducting fluid agree well with the analytical model. 相似文献
97.
Thanh Hai Nguyen Phan Khanh Linh Tran Van An Dinh Duy Thanh Tran Nam Hoon Kim Joong Hee Lee 《Advanced functional materials》2023,33(7):2210101
Development of multifunctional electrocatalysts with high efficiency and stability is of great interest in recent energy conversion technologies. Herein, a novel heteroelectrocatalyst of molecular iron complex (FeMC)-carbide MXene (Mo2TiC2Tx) uniformly embedded in a 3D graphene-based hierarchical network (GrH) is rationally designed. The coexistence of FeMC and MXene with their unique interactions triggers optimum electronic properties, rich multiple active sites, and favorite free adsorption energy for excellent trifunctional catalytic activities. Meanwhile, the highly porous GrH effectively promotes a multichannel architecture for charge transfer and gas/ion diffusion to improve stability. Therefore, the FeMC–MXene/GrH results in superb performances towards oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) in alkaline medium. The practical tests indicate that Zn/Al–air batteries derived from FeMC–MXene/GrH cathodic electrodes produce high power densities of 165.6 and 172.7 mW cm−2, respectively. Impressively, the liquid-state Zn–air battery delivers excellent cycling stability of over 1100 h. In addition, the alkaline water electrolyzer induces a low cell voltage of 1.55 V at 10 mA cm−2 and 1.86 V at 0.4 A cm−2 in 30 wt.% KOH at 80 °C, surpassing recent reports. The achievements suggest an exciting multifunctional electrocatalyst for electrochemical energy applications. 相似文献
98.
Nguyen Dieu My T. Fard Golnar Gharooni Atkins Ashley Bontempo Paul Iuzzolino Michael L. Peleg Orit 《Artificial Life and Robotics》2023,28(1):1-7
Artificial Life and Robotics - Honey bees (Apis mellifera L.) are social insects that makes frequent use of volatile pheromone signals to collectively navigate unpredictable and unknown... 相似文献
99.
Cuong-Le Thanh Nghia-Nguyen Trong Khatir Samir Trong-Nguyen Phuoc Mirjalili Seyedali Nguyen Khuong D. 《Engineering with Computers》2022,38(4):3069-3084
Engineering with Computers - Structural health monitoring (SHM) and Non-destructive Damage Identification (NDI) using responses of structures under dynamic excitation have an imperative role in the... 相似文献
100.
The Journal of Supercomputing - We argue the agent’s low generalization problem for searching target object in challenging visual navigation could be solved by "how" and... 相似文献