全文获取类型
收费全文 | 86786篇 |
免费 | 7960篇 |
国内免费 | 3962篇 |
专业分类
电工技术 | 5167篇 |
技术理论 | 10篇 |
综合类 | 6205篇 |
化学工业 | 14026篇 |
金属工艺 | 4476篇 |
机械仪表 | 4948篇 |
建筑科学 | 6738篇 |
矿业工程 | 2204篇 |
能源动力 | 2318篇 |
轻工业 | 7851篇 |
水利工程 | 1785篇 |
石油天然气 | 4192篇 |
武器工业 | 666篇 |
无线电 | 10247篇 |
一般工业技术 | 10459篇 |
冶金工业 | 4012篇 |
原子能技术 | 982篇 |
自动化技术 | 12422篇 |
出版年
2024年 | 186篇 |
2023年 | 1478篇 |
2022年 | 2463篇 |
2021年 | 3649篇 |
2020年 | 2945篇 |
2019年 | 2399篇 |
2018年 | 2650篇 |
2017年 | 2874篇 |
2016年 | 2717篇 |
2015年 | 3671篇 |
2014年 | 4530篇 |
2013年 | 5362篇 |
2012年 | 5947篇 |
2011年 | 6384篇 |
2010年 | 5364篇 |
2009年 | 5098篇 |
2008年 | 5042篇 |
2007年 | 4626篇 |
2006年 | 4366篇 |
2005年 | 3719篇 |
2004年 | 2698篇 |
2003年 | 2270篇 |
2002年 | 2028篇 |
2001年 | 1804篇 |
2000年 | 1890篇 |
1999年 | 2135篇 |
1998年 | 1795篇 |
1997年 | 1454篇 |
1996年 | 1422篇 |
1995年 | 1200篇 |
1994年 | 1032篇 |
1993年 | 732篇 |
1992年 | 586篇 |
1991年 | 405篇 |
1990年 | 365篇 |
1989年 | 319篇 |
1988年 | 234篇 |
1987年 | 162篇 |
1986年 | 125篇 |
1985年 | 90篇 |
1984年 | 77篇 |
1983年 | 56篇 |
1982年 | 64篇 |
1981年 | 40篇 |
1980年 | 53篇 |
1979年 | 27篇 |
1977年 | 19篇 |
1976年 | 20篇 |
1974年 | 20篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Zhou Yu Fang Bijun Zhang Shuai Lu Xiaolong Ding Jianning 《Journal of Materials Science: Materials in Electronics》2022,33(14):10977-10989
Journal of Materials Science: Materials in Electronics - 0.95(Li0.02Na0.50K0.48)(Nb0.95Sb0.05)O3–0.05AgTaO3@BaZrO3 (LNKNbSAT@BZ) lead-free ceramics were prepared via a sol–gel... 相似文献
2.
Niu Hao Yang Dan-Lei Pu Yuan Wang Dan Wang Jie-Xin 《Journal of Materials Science》2022,57(10):5788-5804
Journal of Materials Science - Nanocomposites have been used in various industries due to their excellent properties. For some of them, high filler content (over 50 wt%) is beneficial to improving... 相似文献
3.
Lu Huaiqian Shi Hui Xie Qilong Li Li Xiao Yong Jia Litao Li Debao 《Catalysis Letters》2022,152(11):3347-3353
Catalysis Letters - This study proposed a new facile route to rational creating oxygen-vacancy (Vo)-rich surface of Co3O4 nanosheets by acetic acid leaching. The acid leached Co3O4 nanosheets was... 相似文献
4.
5.
Mengwei Liu Jin Zhao Shunzo Shimai Dan Han Jian Zhang Shiwei Wang 《Journal of the American Ceramic Society》2022,105(7):4632-4638
MgAl2O4 transparent ceramics were shaped by a commonly used polyacrylic acid (PAA), which acted as both dispersant and gelling agent. The spinel slurries were prepared by ball-milling MgAl2O4 powder, PAA, and water in an attrition mill. The gelling of slurries happened at room temperature in air atmosphere without any other organic additive. The gelling mechanism was the formation of chelates between Mg2+ and carboxyl groups (-COO−) of PAA. The frequency-based testing method was applied to investigate the gelling process of the as-prepared slurry. In addition, a novel in situ characterization method based on a modified indentation testing was invented to better understand the strengthening of the wet green body with time and to guide when demolding could be carried out. After sintering, transparent MgAl2O4 ceramics with high in-line transmittance were resulted. 相似文献
6.
Xiehuan Li Dan Ye 《International Journal of Adaptive Control and Signal Processing》2022,36(1):104-121
In this article, the memory-based dynamic event-triggered controller design issue is investigated for networked interval type-2 (IT2) fuzzy systems under non-periodic denial-of-service (DoS) attacks. For saving limited network bandwidth, a novel memory-based dynamic event-triggered mechanism (DETM) is proposed to schedule data communication. Unlike existing event-triggered generators, the developed memory-based DETM can utilize a series of newly released signals and further save network resources by introducing interval dynamic variables. Moreover, to improve design flexibility, an IT2 fuzzy controller with freely selectable fuzzy rule number and premise membership functions (MFs) is synthesized. Then, a new switched time-delay system with imperfectly matched MFs is established under the consideration of memory-based DETM and DoS attacks simultaneously. Besides, based on the property of MFs, the boundary information of membership grades and slack matrices are introduced in the stability analysis. Furthermore, by using a piecewise Lyapunov–Krasovskii method, membership-functions-dependent criteria are deduced to ensure the asymptotic stability of built fuzzy switched systems. Finally, the effectiveness of proposed control strategies is demonstrated by simulation examples. 相似文献
7.
Lu Tao Wang Yishuang Deng Yan Wu Chengqian Li Xiangqi Wang Guotai 《Magma (New York, N.Y.)》2022,35(6):1009-1020
Magnetic Resonance Materials in Physics, Biology and Medicine - To evaluate the placental function by monoexponential, biexponential, and diffusion kurtosis MR imaging (MRI) in patients with... 相似文献
8.
Janardhan Rahul Kallada Shakil Saani Hassinen Marko Lu Wei Puttonen Jari Hostikka Simo 《Fire Technology》2022,58(4):2405-2440
Fire Technology - The feasibility of coupled computational fluid dynamics (CFD) and finite element (FE) simulations to aid the planning of fire intervention tactics and the effectiveness of... 相似文献
9.
肝损伤(liver injury)是指基因遗传或外部原因诱发的肝脏功能异常性疾病.临床表现为食欲不振、乏力、恶心、黄疸、疲乏等,严重者将出现肝功能衰竭,致死风险极高.在交通肇事、暴力犯罪及意外事件中,肝由于体积大、位置固定、质地脆弱、血运丰富等原因,往往是最容易发生损伤的器官之一,肝损伤后的死亡率可高达10.5%~25%[1].随着时间的变化,肝损伤的程度、病理改变、GM-CSF等相关细胞因子及CBS等相关酶的表达水平也会进一步变化.肝损伤后,由于肝内部环境稳态的破坏,器官的状态、结构、各种蛋白的转录水平、蛋白及细胞因子的表达变化水平也会发生一定程度的改变.因此定性定量地分析这些变化,找到时间相关性强的特异性指标,对于指导法医学的实践具有重要的作用.因此在法医学鉴定中,通过肝脏损伤及病变程度的改变,明确肝损伤病变与死亡时间的关系有利于判断事件或案件性质,并有助于进一步对责任方的认定. 相似文献
10.
Neural Processing Letters - Semi-supervised learning techniques have been attracting increasing interests in many machine learning fields for its effectiveness in using labeled and unlabeled... 相似文献