全文获取类型
收费全文 | 6437篇 |
免费 | 441篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 95篇 |
综合类 | 12篇 |
化学工业 | 1908篇 |
金属工艺 | 141篇 |
机械仪表 | 162篇 |
建筑科学 | 143篇 |
矿业工程 | 16篇 |
能源动力 | 272篇 |
轻工业 | 787篇 |
水利工程 | 44篇 |
石油天然气 | 30篇 |
武器工业 | 1篇 |
无线电 | 510篇 |
一般工业技术 | 1434篇 |
冶金工业 | 492篇 |
原子能技术 | 70篇 |
自动化技术 | 779篇 |
出版年
2024年 | 12篇 |
2023年 | 68篇 |
2022年 | 196篇 |
2021年 | 301篇 |
2020年 | 164篇 |
2019年 | 198篇 |
2018年 | 221篇 |
2017年 | 240篇 |
2016年 | 246篇 |
2015年 | 190篇 |
2014年 | 334篇 |
2013年 | 482篇 |
2012年 | 409篇 |
2011年 | 456篇 |
2010年 | 352篇 |
2009年 | 361篇 |
2008年 | 351篇 |
2007年 | 300篇 |
2006年 | 224篇 |
2005年 | 189篇 |
2004年 | 157篇 |
2003年 | 165篇 |
2002年 | 155篇 |
2001年 | 112篇 |
2000年 | 81篇 |
1999年 | 89篇 |
1998年 | 140篇 |
1997年 | 110篇 |
1996年 | 84篇 |
1995年 | 64篇 |
1994年 | 59篇 |
1993年 | 52篇 |
1992年 | 37篇 |
1991年 | 28篇 |
1990年 | 40篇 |
1989年 | 25篇 |
1988年 | 33篇 |
1987年 | 17篇 |
1986年 | 16篇 |
1985年 | 14篇 |
1984年 | 19篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1977年 | 6篇 |
1976年 | 11篇 |
1974年 | 6篇 |
1972年 | 6篇 |
排序方式: 共有6896条查询结果,搜索用时 296 毫秒
1.
2.
Olga Yu Kurapova Sergey M. Shugurov Evgenia A. Vasil'eva Daniil A. Savelev Vladimir G. Konakov Sergey I. Lopatin 《Ceramics International》2021,47(8):11072-11079
Ceria-based solid solutions are important materials for high- and medium-temperature electrochemical applications. However, the stabilities of both binary and ternary ceria-based solid solutions are insufficient at elevated temperatures, which limits their application as solid electrolytes or SOFC cathodes. Data on the high-temperature stability of ceria-based ceramics are unavailable in the literature. In the present study, we report a thermodynamic stability investigation of Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions. The thermal prehistories of binary and ternary systems were investigated using STA, XRD, and ESCA techniques. The vaporization processes were investigated in the temperature range of 1577–2227°С via the Knudsen effusion mass spectrometry technique. Using data on the component activity in solid-phase thermodynamic properties of Y2O3-CeO2 solid solutions, which is represented as the Gibbs energy, the excess Gibbs energy was calculated as a function of the ceria mol. %. It was shown that the reduction of Ce4+ to Ce3+ in Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions corresponds to less-negative Gibbs energy compared to ZrO2-CeO2 solid solutions. 相似文献
3.
4.
5.
6.
7.
8.
9.
P. Carrasqueira H. Rocha J. M. Dias T. Ventura B. C. Ferreira M. C. Lopes 《International Transactions in Operational Research》2023,30(1):206-223
Radiation therapy is a technology-driven cancer treatment modality that has experienced significant advances over the last decades, due to multidisciplinary contributions that include engineering and computing. Recent technological developments allow the use of noncoplanar volumetric modulated arc therapy (VMAT), one of the most recent photon treatment techniques, in clinical practice. In this work, an automated noncoplanar arc trajectory optimization framework designed in two modular phases is presented. First, a noncoplanar beam angle optimization algorithm is used to obtain a set of noncoplanar irradiation directions. Then, anchored in these directions, an optimization strategy is proposed to compute an optimal arc trajectory. The computational experiments considered a pool of twelve difficult head-and-neck tumor cases. It was possible to observe that, for some of these cases, the optimized noncoplanar arc trajectories led to significant treatment planning quality improvements, when compared with coplanar VMAT treatment plans. Although these experiments were done in a research environment treatment planning software (matRad), the conclusions can be of interest for a clinical setting: automated procedures can simplify the current treatment workflow, produce high-quality treatment plans, making better use of human resources and allowing for unbiased comparisons between different treatment techniques. 相似文献
10.
An effective practical approach that allows not only a significant reduction in the scope of practical experiments in the course of studying suspension separation processes in hydrocyclones, but also makes it possible to assess the intensity of random components of the processes and define the interrelation between such components and hydrodynamics of flows in a hydrocyclone is presented. Within the frames of the developed probabilistic‐statistical model of suspension separation in hydrocyclones on the basis of statistical self‐similarity properties, a relationship was found between determined and random components of the processes. This allowed transitioning from three‐parameter probability density functions for suspension particles in hydrocyclones to two‐parameter functions; thus significantly improving the efficiency of practical application of the developed model. 相似文献