全文获取类型
收费全文 | 13432篇 |
免费 | 1312篇 |
国内免费 | 531篇 |
专业分类
电工技术 | 844篇 |
技术理论 | 2篇 |
综合类 | 885篇 |
化学工业 | 2253篇 |
金属工艺 | 957篇 |
机械仪表 | 881篇 |
建筑科学 | 930篇 |
矿业工程 | 356篇 |
能源动力 | 371篇 |
轻工业 | 771篇 |
水利工程 | 254篇 |
石油天然气 | 993篇 |
武器工业 | 114篇 |
无线电 | 1473篇 |
一般工业技术 | 1595篇 |
冶金工业 | 757篇 |
原子能技术 | 157篇 |
自动化技术 | 1682篇 |
出版年
2024年 | 66篇 |
2023年 | 240篇 |
2022年 | 434篇 |
2021年 | 595篇 |
2020年 | 438篇 |
2019年 | 377篇 |
2018年 | 455篇 |
2017年 | 452篇 |
2016年 | 441篇 |
2015年 | 563篇 |
2014年 | 670篇 |
2013年 | 868篇 |
2012年 | 836篇 |
2011年 | 919篇 |
2010年 | 809篇 |
2009年 | 751篇 |
2008年 | 769篇 |
2007年 | 727篇 |
2006年 | 681篇 |
2005年 | 607篇 |
2004年 | 386篇 |
2003年 | 315篇 |
2002年 | 363篇 |
2001年 | 322篇 |
2000年 | 323篇 |
1999年 | 379篇 |
1998年 | 288篇 |
1997年 | 252篇 |
1996年 | 203篇 |
1995年 | 180篇 |
1994年 | 124篇 |
1993年 | 113篇 |
1992年 | 80篇 |
1991年 | 57篇 |
1990年 | 47篇 |
1989年 | 47篇 |
1988年 | 26篇 |
1987年 | 19篇 |
1986年 | 18篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Peng Wang Yan Li Yujiao Qu Baowei Wang Jingxin Sun Chunwei Miao Ming Huang He Huang Congxiang Zhang 《International Journal of Food Science & Technology》2022,57(6):3428-3439
The effects of cellulose microfibres (CMFs, Average size: 100 ± 5 μm) and cellulose nanofibres (CNFs, Average size: 60 ± 3 nm) on the properties of myofibrillar protein (MP) gels from duck breast meat were studied. The results demonstrated that CMFs and CNFs were mostly connected to MP by non-covalent bonds, the diffusion and cross-linking of MP molecules was promoted, and a denser and more complete gel network was formed. With the increases of CMFs and CNFs concentration (0–10%), the hardness was increased by 13.15% and 19.78% for CMFs10% and CNFs10% gels, respectively, and the elasticity was increased by 40% and 80%, respectively. At the same concentration (0–10%), the increase in gel hardness, viscoelasticity and immobilised water content was greater in the CNFs-MP group than in the CMFs-MP group. The CNFs-MP group had a tighter gel network, and CNFs had a better potential to improve the gelation performance of MP. 相似文献
2.
Fine-grained few-shot learning is a difficult task in image classification. The reason is that the discriminative
features of fine-grained images are often located in local areas of the image, while most of the existing few-shotlearning image classification methods only use top-level features and adopt a single measure. In that way, the localfeatures of the sample cannot be learned well. In response to this problem, ensemble relation network with multi-level measure (ERN-MM) is proposed in this paper. It adds the relation modules in the shallow feature space tocompare the similarity between the samples in the local features, and finally integrates the similarity scores from thefeature spaces to assign the label of the query samples. So the proposed method ERN-MM can use local details andglobal information of different grains. Experimental results on different fine-grained datasets show that the proposedmethod achieves good classification performance and also proves its rationality. 相似文献
3.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018)
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
4.
5.
Chengxiao Zhao Zupeng Chen Run Shi Xiaofei Yang Tierui Zhang 《Advanced materials (Deerfield Beach, Fla.)》2020,32(28):1907296
With the ambition of solving the challenges of the shortage of fossil fuels and their associated environmental pollution, visible-light-driven splitting of water into hydrogen and oxygen using semiconductor photocatalysts has emerged as a promising technology to provide environmentally friendly energy vectors. Among the current library of developed photocatalysts, organic conjugated polymers present unique advantages of sufficient light-absorption efficiency, excellent stability, tunable electronic properties, and economic applicability. As a class of rising photocatalysts, organic conjugated polymers offer high flexibility in tuning the framework of the backbone and porosity to fulfill the requirements for photocatalytic applications. In the past decade, significant progress has been made in visible-light-driven water splitting employing organic conjugated polymers. The recent development of the structural design principles of organic conjugated polymers (including linear, crosslinked, and supramolecular self-assembled polymers) toward efficient photocatalytic hydrogen evolution, oxygen evolution, and overall water splitting is described, thus providing a comprehensive reference for the field. Finally, current challenges and perspectives are also discussed. 相似文献
6.
Wang Yunfei Zheng Wang Zhang Xiaofei Shen Jinqing 《Multidimensional Systems and Signal Processing》2020,31(3):907-926
Multidimensional Systems and Signal Processing - Generalized coprime structure decomposes the interleaved subarrays in the conventional coprime array by introducing a displacement and the resulting... 相似文献
7.
Dongdong Ji Zheng Liu Bailing Jiang Xiaofei Luo 《International Journal of Hydrogen Energy》2021,46(27):13960-13970
The evaluation of cell's weatherability is of practical interest. To further improve the soluble lead flow battery's weatherability, physiochemical properties of electrolytes containing fluoborate, perchlorate, methanesulfonate and trifluoromethanesulfonate are investigated from ?60 to 50 °C. Activities of CF3SO3H and HClO4 are poor in trifluoromethanesulfonate and perchlorate solutions due to common anion effect. The solubility of lead salt can be improved by increasing temperature, but worsened by increasing acid's content. With the temperature increasing, the conductivity is enhanced, and the viscosity is lowered for four solutions. The same results have been found by increasing acid's content except for CF3SO3H. The high energy efficiency can be achieved for cells over ?40–0 °C using fluoborate and perchlorate solutions, 73.2% at ?40 °C and 78.1% at ?30 °C respectively. Over the temperature range of 20–50 °C, the cells with methanesulfonate and trifluoromethanesulfonate solutions have good performance, 77.4% and 73.7% at 50 °C respectively. 相似文献
8.
9.
10.