全文获取类型
收费全文 | 7153篇 |
免费 | 237篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 100篇 |
综合类 | 4篇 |
化学工业 | 1244篇 |
金属工艺 | 80篇 |
机械仪表 | 120篇 |
建筑科学 | 245篇 |
矿业工程 | 8篇 |
能源动力 | 161篇 |
轻工业 | 670篇 |
水利工程 | 73篇 |
石油天然气 | 24篇 |
无线电 | 641篇 |
一般工业技术 | 1341篇 |
冶金工业 | 1911篇 |
原子能技术 | 43篇 |
自动化技术 | 731篇 |
出版年
2023年 | 27篇 |
2022年 | 44篇 |
2021年 | 119篇 |
2020年 | 80篇 |
2019年 | 86篇 |
2018年 | 127篇 |
2017年 | 114篇 |
2016年 | 114篇 |
2015年 | 85篇 |
2014年 | 140篇 |
2013年 | 403篇 |
2012年 | 287篇 |
2011年 | 369篇 |
2010年 | 269篇 |
2009年 | 270篇 |
2008年 | 310篇 |
2007年 | 323篇 |
2006年 | 271篇 |
2005年 | 255篇 |
2004年 | 239篇 |
2003年 | 216篇 |
2002年 | 217篇 |
2001年 | 157篇 |
2000年 | 151篇 |
1999年 | 126篇 |
1998年 | 297篇 |
1997年 | 220篇 |
1996年 | 185篇 |
1995年 | 146篇 |
1994年 | 136篇 |
1993年 | 155篇 |
1992年 | 98篇 |
1991年 | 67篇 |
1990年 | 89篇 |
1989年 | 110篇 |
1988年 | 104篇 |
1987年 | 81篇 |
1986年 | 83篇 |
1985年 | 90篇 |
1984年 | 60篇 |
1983年 | 65篇 |
1982年 | 56篇 |
1981年 | 71篇 |
1980年 | 45篇 |
1979年 | 56篇 |
1978年 | 39篇 |
1977年 | 74篇 |
1976年 | 70篇 |
1975年 | 34篇 |
1972年 | 24篇 |
排序方式: 共有7396条查询结果,搜索用时 15 毫秒
1.
2.
Neural Computing and Applications - With an increase in online longitudinal users’ interactions, capturing users’ precise preferences and giving accurate recommendations have become an... 相似文献
3.
Timothy Zurrer Kenneth Wong Jonathan Horlyck Emma C. Lovell Joshua Wright Nicholas M. Bedford Zhaojun Han Kang Liang Jason Scott Rose Amal 《Advanced functional materials》2021,31(9):2007624
The vast chemical and structural tunability of metal–organic frameworks (MOFs) are beginning to be harnessed as functional supports for catalytic nanoparticles spanning a range of applications. However, a lack of straightforward methods for producing nanoparticle-encapsulated MOFs as efficient heterogeneous catalysts limits their usage. Herein, a mixed-metal MOF, NiMg-MOF-74, is utilized as a template to disperse small Ni nanoclusters throughout the parent MOF. By exploiting the difference in Ni O and Mg O coordination bond strength, Ni2+ is selectively reduced to form highly dispersed Ni nanoclusters constrained by the parent MOF pore diameter, while Mg2+ remains coordinated in the framework. By varying the ratio of Ni to Mg in the parent MOF, accessible surface area and crystallinity can be tuned upon thermal treatment, influencing CO2 adsorption capacity and hydrogenation selectivity. The resulting Ni nanoclusters prove to be an active catalyst for CO2 methanation and are examined using extended X-ray absorption fine structure and X-ray photoelectron spectroscopy. By preserving a segment of the Mg2+-containing MOF framework, the composite system retains a portion of its CO2 adsorption capacity while continuing to deliver catalytic activity. The approach is thus critical for designing materials that can bridge the gap between carbon capture and CO2 utilization. 相似文献
4.
Locke Davenport Huyer Serena Mandla Yufeng Wang Scott B. Campbell Bess Yee Christian Euler Benjamin F. Lai A. Dawn Bannerman Dawn S. Y. Lin Miles Montgomery Kayla Nemr Timothy Bender Slava Epelman Radhakrishnan Mahadevan Milica Radisic 《Advanced functional materials》2021,31(6):2003341
Itaconate (ITA) is an emerging powerhouse of innate immunity with therapeutic potential that is limited in its ability to be administered in a soluble form. A library of polyester materials that incorporate ITA into polymer backbones resulting in materials with inherent immunoregulatory behavior is developed. Harnessing hydrolytic degradation release from polyester backbones, ITA polymers result in the mechanism specific immunoregulatory properties on macrophage polarization in vitro. In a functional assay, the polymer-released ITA inhibits bacterial growth on acetate. Translation to an in vivo model of biomaterial associated inflammation, intraperitoneal injection of ITA polymers demonstrate a rapid resolution of inflammation in comparison to a control polymer silicone, demonstrating the value of sustained biomimetic presentation of ITA. 相似文献
5.
Effendi Rusli Timothy O. Drews David L. Ma Richard C. Alkire Richard D. Braatz 《Journal of Process Control》2006,16(4):409-417
Robust nonlinear feedforward–feedback controllers are designed for a multiscale system that dynamically couples kinetic Monte Carlo (KMC) and finite difference (FD) simulation codes. The coupled codes simulate the copper electrodeposition process for manufacturing on-chip copper interconnects in electronic devices. The control objective is to regulate the current density subject to the condition that the steady-state fluctuation of the overpotential remains bounded within ±0.01 V. The controller designs incorporate a low-order stochastic model that captures the input–output behavior of the coupled KMC–FD code. The controllers achieve the objectives and the closed-loop responses implemented on the low-order model and the coupled KMC–FD code match well within stochastic variations. The nonlinear feedforward control reduces the rise time of the controller response while the feedback control ensures robustness in the presence of model uncertainty. 相似文献
6.
The applicability of the identical elements (IE) model of arithmetic fact retrieval (T. C. Rickard, A. F. Healy, & L. E. Bourne, 1994) to cued recall from episodic (image and sentence) memory was explored in 3 transfer experiments. In agreement with results from arithmetic, speedup following even minimal practice recalling a missing word from an episodically bound word triplet did not transfer positively to other cued recall items involving the same triplet. The shape of the learning curve further supported a shift from episode-based to IE-based recall, extending some models of skill learning to cued recall practice. In contrast with previous findings, these results indicate that a form of representation that is independent of the original episodic memory underlies cued-recall performance following minimal practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
8.
Crosstalk between microstrip transmission lines 总被引:1,自引:0,他引:1
Hill D.A. Cavcey K.H. Johnk R.T. 《Electromagnetic Compatibility, IEEE Transactions on》1994,36(4):314-321
Methods for prediction of crosstalk between microstrip transmission lines are reviewed and simplified for the weak-coupling case. Classical coupled transmission line theory is used for uniform lines, and potential and induced EMF methods are used for crosstalk between nonuniform lines. It is shown that the potential method is equivalent to classical coupled transmission line theory for the case of uniform lines. An experiment was performed for uniform coupled microstrip lines for frequencies from 50 MHz to 5 GHz, and good agreement between theory and measurement was obtained for both near- and far-end crosstalk 相似文献
9.
D Galasko T Saitoh Y Xia LJ Thal R Katzman LR Hill L Hansen 《Canadian Metallurgical Quarterly》1994,44(10):1950-1951
We determined apolipoprotein E (ApoE) genotypes in 122 autopsied demented patients. The frequency of the ApoE epsilon 4 allele was 39.6% in Alzheimer's disease (AD), 29.0% in the Lewy body variant of AD (LBV), and 6.25% in diffuse Lewy body disease. For AD and LBV patients, the epsilon 4 frequency was significantly higher than that reported in nondemented controls (10 to 15%). Therefore, LBV and AD share ApoE epsilon 4 as a genetic risk factor, providing further evidence that these conditions overlap. 相似文献
10.