全文获取类型
收费全文 | 9710篇 |
免费 | 952篇 |
国内免费 | 778篇 |
专业分类
电工技术 | 1020篇 |
综合类 | 735篇 |
化学工业 | 1721篇 |
金属工艺 | 595篇 |
机械仪表 | 322篇 |
建筑科学 | 253篇 |
矿业工程 | 127篇 |
能源动力 | 263篇 |
轻工业 | 389篇 |
水利工程 | 99篇 |
石油天然气 | 177篇 |
武器工业 | 44篇 |
无线电 | 1217篇 |
一般工业技术 | 692篇 |
冶金工业 | 497篇 |
原子能技术 | 275篇 |
自动化技术 | 3014篇 |
出版年
2024年 | 22篇 |
2023年 | 113篇 |
2022年 | 225篇 |
2021年 | 241篇 |
2020年 | 219篇 |
2019年 | 168篇 |
2018年 | 165篇 |
2017年 | 217篇 |
2016年 | 271篇 |
2015年 | 279篇 |
2014年 | 471篇 |
2013年 | 512篇 |
2012年 | 681篇 |
2011年 | 793篇 |
2010年 | 808篇 |
2009年 | 950篇 |
2008年 | 832篇 |
2007年 | 879篇 |
2006年 | 762篇 |
2005年 | 465篇 |
2004年 | 365篇 |
2003年 | 320篇 |
2002年 | 339篇 |
2001年 | 240篇 |
2000年 | 212篇 |
1999年 | 174篇 |
1998年 | 105篇 |
1997年 | 100篇 |
1996年 | 70篇 |
1995年 | 70篇 |
1994年 | 46篇 |
1993年 | 55篇 |
1992年 | 38篇 |
1991年 | 41篇 |
1990年 | 36篇 |
1989年 | 28篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 16篇 |
1980年 | 12篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
David Bravo Katherine Zepeda-Morales Carola J. Maturana Jeffri S. Retamal Alejandro Hernndez Teresa Pelissier Rafael Barra Patricio Sez-Briones Hctor Burgos Luis Constandil 《International journal of molecular sciences》2022,23(12)
Pannexin 1 (Panx1) is involved in the spinal central sensitization process in rats with neuropathic pain, but its interaction with well-known, pain-related, ligand-dependent receptors, such as NMDA receptors (NMDAR) and P2X7 purinoceptors (P2X7R), remains largely unexplored. Here, we studied whether NMDAR- and P2X7R-dependent nociceptive signaling in neuropathic rats require the activation of Panx1 channels to generate spinal central sensitization, as assessed by behavioral (mechanical hyperalgesia) and electrophysiological (C-reflex wind-up potentiation) indexes. Administration of either a selective NMDAR agonist i.t. (NMDA, 2 mM) or a P2X7R agonist (BzATP, 150 μM) significantly increased both the mechanical hyperalgesia and the C-reflex wind-up potentiation, effects that were rapidly reversed (minutes) by i.t. administration of a selective pannexin 1 antagonist (10panx peptide, 300 μM), with the scores even reaching values of rats without neuropathy. Accordingly, 300 μM 10panx completely prevented the effects of NMDA and BzATP administered 1 h later, on mechanical hyperalgesia and C-reflex wind-up potentiation. Confocal immunofluorescence imaging revealed coexpression of Panx1 with NeuN protein in intrinsic dorsal horn neurons of neuropathic rats. The results indicate that both NMDAR- and P2X7R-mediated increases in mechanical hyperalgesia and C-reflex wind-up potentiation require neuronal Panx1 channel activation to initiate and maintain nociceptive signaling in neuropathic rats. 相似文献
32.
33.
西藏金河水电站采用GIS全封闭组合电器,它改善了恶劣环境对电气设备的危害,提高了供电的可靠性及电站综合自动化水平,有利于运行管理。GIS设备在金河电站的成功应用说明,GIS完全可以在西藏地区推广应用.这也完全符合电力行业的发展趋势。 相似文献
34.
F.J. Liu M.C. Zhang J.X. Dong Y. W. Zhang 《金属学报(英文版)》2007,20(2):102-110
High temperature oxidation behaviors of FGH96 P/M superalloy have been studied in air at temperatures ranging from 600 to 1000℃. By means of isothermal oxidation testing,X-ray diffraction,SEM(scanning electron microscopy),and EDS(energy dispersive X-ray spectroscopy) analyses,the oxidation kinetics as well as the composition and morphology of scales were investigated. Thermodynamic calculations were used to explain the oxidation mechanism. The results showed that as the oxidation temperature increased,the oxidation rate,the scale thickness,and scale spallation increased. FGH96 P/M superalloy exhibits good oxidation resistance at temperature below 800℃. The oxidation kinetics follows an approximately parabolic rate law,and the oxide layer was mainly composed of Cr2O3,TiO2,and a little amount of NiCr2O4. The oxidation is controlled by the transmission of chromium,titanium,and oxygen through the oxide scale. 相似文献
35.
Claudio Bernardazzi Morgana Teixeira Lima Castelo-Branco Beatriz Pêgo Beatriz Elias Ribeiro Siane Lopes Bittencourt Rosas Patrícia Teixeira Santana Joo Carlos Machado Camille Leal Fabiano Thompson Robson Coutinho-Silva Heitor Siffert Pereira de Souza 《International journal of molecular sciences》2022,23(9)
36.
37.
酸度对P204-HCl-H3AOH体系萃取La(Ⅲ)的机理影响 总被引:1,自引:1,他引:0
在pH >1、0204-煤油体系以及P204-HCl-H3AOH 体系负载La有机相进行红外光谱测试,研究了酸度对P204-HCl-H3AOH 体系萃取La(Ⅲ)的机理影响。研究结果表明,当pH>1时,萃取过程的实质是La离子与P-OH 置换,遵循阳离子交换机制;0相似文献
38.
39.
Self‐Powered Trace Memorization by Conjunction of Contact‐Electrification and Ferroelectricity 下载免费PDF全文
Xiangyu Chen Mitsumasa Iwamoto Zhemin Shi Limin Zhang Zhong Lin Wang 《Advanced functional materials》2015,25(5):739-747
Triboelectric nanogenerator (TENG) is a newly invented technology that can effectively harvest ambient mechanical energy from various motions with promising applications in portable electronics, self‐powered sensor networks, etc. Here, by coupling TENG and a thin film of ferroelectric polymer, a new application is designed for TENG as a self‐powered memory system for recording a mechanical displacement/trace. The output voltage produced by the TENG during motion can polarize the dipole moments in the ferroelectric thin film. Later, by applying a displacement current measurement to detect the polarization density in the ferroelectric film, the motion information of the TENG can be directly read. The sliding TENG and the single‐electrode TENG matrix are both utilized for realizing the memorization of the motion trace in one‐dimensional and two‐dimensional space, respectively. Currently, the ferroelectric thin film with a size of 3.1 mm2 can record a minimum area changing of 30 mm2 and such resolution can still be possibly improved. These results prove that the ferroelectric polymer is an effective memory material to work together with TENG and thereby the fabricated memory system can potentially be used as a self‐powered displacement monitor. 相似文献
40.