全文获取类型
收费全文 | 82841篇 |
免费 | 15793篇 |
国内免费 | 156篇 |
专业分类
电工技术 | 1404篇 |
综合类 | 66篇 |
化学工业 | 26285篇 |
金属工艺 | 2455篇 |
机械仪表 | 3952篇 |
建筑科学 | 2692篇 |
矿业工程 | 25篇 |
能源动力 | 2873篇 |
轻工业 | 10401篇 |
水利工程 | 548篇 |
石油天然气 | 132篇 |
武器工业 | 2篇 |
无线电 | 13245篇 |
一般工业技术 | 20517篇 |
冶金工业 | 4400篇 |
原子能技术 | 668篇 |
自动化技术 | 9125篇 |
出版年
2024年 | 24篇 |
2023年 | 539篇 |
2022年 | 677篇 |
2021年 | 1671篇 |
2020年 | 2334篇 |
2019年 | 3961篇 |
2018年 | 4196篇 |
2017年 | 4427篇 |
2016年 | 5179篇 |
2015年 | 4816篇 |
2014年 | 5500篇 |
2013年 | 7588篇 |
2012年 | 5711篇 |
2011年 | 6014篇 |
2010年 | 5196篇 |
2009年 | 5192篇 |
2008年 | 4673篇 |
2007年 | 3899篇 |
2006年 | 3536篇 |
2005年 | 2971篇 |
2004年 | 2805篇 |
2003年 | 2704篇 |
2002年 | 2479篇 |
2001年 | 2149篇 |
2000年 | 1992篇 |
1999年 | 1350篇 |
1998年 | 1600篇 |
1997年 | 1031篇 |
1996年 | 823篇 |
1995年 | 570篇 |
1994年 | 480篇 |
1993年 | 420篇 |
1992年 | 304篇 |
1991年 | 287篇 |
1990年 | 267篇 |
1989年 | 246篇 |
1988年 | 209篇 |
1987年 | 178篇 |
1986年 | 127篇 |
1985年 | 118篇 |
1984年 | 95篇 |
1983年 | 66篇 |
1982年 | 38篇 |
1981年 | 41篇 |
1980年 | 31篇 |
1979年 | 31篇 |
1978年 | 31篇 |
1977年 | 39篇 |
1976年 | 61篇 |
1973年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Koji Morita Byung-Nam Kim Hidehiro Yoshida Keijiro Hiraga Yoshio Sakka 《Journal of the European Ceramic Society》2018,38(6):2588-2595
Carbon contamination from the carbon paper/dies during spark-plasma-sintering (SPS) processing was examined in the MgAl2O4 spinel. The carbon contamination sensitively changes with the heating rate during the SPS processing. At the high heating rate of 100 °C/min, the carbon contamination having organized structures occurred over almost the entire area from the surface to deep inside the SPSed spinel disk. In contrast, at the slow heating rate of 10 °C/min, the carbon contamination having disordered structures occurred only around the surface area. The carbon phases transform into high pressure CO/CO2 gases by post-annealing in air and lead to pore formation along the grain junctions. The pore formation significantly occurs at the high heating rate due to the large amount of the contaminant carbon phases. This suggests that if once the carbon contamination was formed in the materials, it is very difficult to remove the carbon phases from the materials. 相似文献
102.
Min-Kyung Kang Soo-Il Kim Su Yeon Oh Woojin Na Young-Hee Kang 《International journal of molecular sciences》2020,21(22)
Podocyte injury inevitably results in leakage of proteins from the glomerular filter and is vital in the pathogenesis of diabetic nephropathy (DN). The underlying mechanisms of podocyte injury facilitate finding of new therapeutic targets for DN treatment and prevention. Tangeretin is an O-polymethoxylated flavone present in citrus peels with anti-inflammatory and antioxidant properties. This study investigated the renoprotective effects of tangeretin on epithelial-to-mesenchymal transition-mediated podocyte injury and fibrosis through oxidative stress and hypoxia caused by hyperglycemia. Mouse podocytes were incubated in media containing 33 mM glucose in the absence and presence of 1–20 μM tangeretin for up to 6 days. The in vivo animal model employed db/db mice orally administrated with 10 mg/kg tangeretin for 8 weeks. Non-toxic tangeretin inhibited glucose-induced expression of the mesenchymal markers of N-cadherin and α-smooth muscle actin in podocytes. However, the reduced induction of the epithelial markers of E-cadherin and P-cadherin was restored by tangeretin in diabetic podocytes. Further, tangeretin enhanced the expression of the podocyte slit diaphragm proteins of nephrin and podocin down-regulated by glucose stimulation. The transmission electron microscopic images revealed that foot process effacement and loss of podocytes occurred in diabetic mouse glomeruli. However, oral administration of 10 mg/kg tangeretin reduced urine albumin excretion and improved foot process effacement of diabetic podocytes through inhibiting loss of slit junction and adherenes junction proteins. Glucose enhanced ROS production and HIF-1α induction in podocytes, leading to induction of oxidative stress and hypoxia. Similarly, in diabetic glomeruli reactive oxygen species (ROS) production and HIF-1α induction were observed. Furthermore, hypoxia-evoking cobalt chloride induced epithelial-to-mesenchymal transition (EMT) process and loss of slit diaphragm proteins and junction proteins in podocytes, which was inhibited by treating submicromolar tangeretin. Collectively, these results demonstrate that tangeretin inhibited podocyte injury and fibrosis through blocking podocyte EMT caused by glucose-induced oxidative stress and hypoxia. 相似文献
103.
104.
Application of high‐temperature Fenton oxidation for the treatment of sulfonation plant wastewater 下载免费PDF全文
105.
106.
This paper considers a novel distributed iterative learning consensus control algorithm based on neural networks for the control of heterogeneous nonlinear multiagent systems. The system's unknown nonlinear function is approximated by suitable neural networks; the approximation error is countered by a robust term in the control. Two types of control algorithms, both of which utilize distributed learning laws, are provided to achieve consensus. In the provided control algorithms, the desired reference is considered to be an unknown factor and then estimated using the associated learning laws. The consensus convergence is proven by the composite energy function method. A numerical simulation is ultimately presented to demonstrate the efficacy of the proposed control schemes. 相似文献
107.
108.
109.
110.
Ricardo Cambraia Parreira Diana Paola Gmez‐Mendoza Itamar Couto Guedes de Jesus Rafael Pereira Lemos Anderson Kennedy Santos Cristiana Perdigo Rezende Henrique Csar Pereira Figueiredo Mauro Cunha Xavier Pinto Frank Kjeldsen Silvia Guatimosim Rodrigo Ribeiro Resende Thiago Verano‐Braga 《Proteomics. Clinical applications》2020,14(4)