全文获取类型
收费全文 | 1438篇 |
免费 | 185篇 |
国内免费 | 74篇 |
学科分类
工业技术 | 1697篇 |
出版年
2024年 | 12篇 |
2023年 | 43篇 |
2022年 | 75篇 |
2021年 | 85篇 |
2020年 | 71篇 |
2019年 | 46篇 |
2018年 | 61篇 |
2017年 | 55篇 |
2016年 | 39篇 |
2015年 | 69篇 |
2014年 | 78篇 |
2013年 | 98篇 |
2012年 | 109篇 |
2011年 | 125篇 |
2010年 | 100篇 |
2009年 | 91篇 |
2008年 | 90篇 |
2007年 | 53篇 |
2006年 | 74篇 |
2005年 | 46篇 |
2004年 | 42篇 |
2003年 | 39篇 |
2002年 | 22篇 |
2001年 | 26篇 |
2000年 | 27篇 |
1999年 | 31篇 |
1998年 | 26篇 |
1997年 | 19篇 |
1996年 | 12篇 |
1995年 | 15篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 3篇 |
1985年 | 1篇 |
1980年 | 1篇 |
1951年 | 2篇 |
排序方式: 共有1697条查询结果,搜索用时 0 毫秒
1.
Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii 下载免费PDF全文
Wen Li Xiaobei Li Yan Yang Feng Zhou Yanfang Liu Shuai Zhou Hailong Yu 《International Journal of Food Science & Technology》2015,50(11):2360-2366
Pleurotus eryngii, the second largest industrial cultivation mushroom in China, is usually cultivated on substrates mainly consisting of sawdust and corncob. In this study, experiments were performed to determine the effects of different carbon sources and C/N values on nonvolatile taste components of P. eryngii. The effects of different carbon sources on nonvolatile taste components levels revealed that sawdust was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while corncob was beneficial to high contents of carbohydrate, polysaccharides and trehalose. At the similar C/N values, relatively higher sawdust content was beneficial to umami amino acid production, while relatively higher corncob content was beneficial to high contents of carbohydrate, polysaccharides and mannitol. Higher C/N value was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while lower C/N value was beneficial to high contents of carbohydrate, polysaccharides and trehalose. These results provided information for P. eryngii fruit body industrial cultivation to obtain specific nonvolatile taste components with high levels. 相似文献
2.
介绍了烟气轮机径向轴承轴瓦手工刮削式和机加工偏心式的特点和加工制造,并通过数据分析,指出了机加工偏心式轴瓦的优点。 相似文献
3.
Ye Yuan Yanfang Li Cameron B.D. Relue P. 《IEEE journal of selected topics in quantum electronics》2007,13(6):1671-1679
In this study, we wanted to see if fluorescence anisotropy could be used to detect changes in metabolism in cells with significant light scattering and absorption properties. Fluorescence anisotropy measurements of nicotinamide adenine dinucleotide (NADH) were performed with human melanocytes and melanoma cell lines. To demonstrate the feasibility of using fluorescence anisotropy for detecting metabolic changes, the electron transport chain was blocked using rotenone, inducing an accumulation of intracellular NADH. Total fluorescence increased in all cells as a result of rotenone treatment. Fluorescence anisotropy decreased in the rotenone-treated cells relative to the controls, suggesting an increased ratio of free to protein-bound NADH in the treated cells. In general, the fluorescence anisotropy of the melanocytes was significantly higher than that of the melanoma cell lines. Reflectance spectroscopy showed that the differences in fluorescence anisotropy between the cell types were not due to differences in scattering and absorption properties. Intrinsic cellular NADH fluorescence was experimentally extracted by ratioing polarized fluorescence to polarized reflectance. NADH binding, measured as the ratio of fluorescence intensity at 430 and 465 nm, showed more protein-bound NADH in the melanocytes than in the melanoma cells, consistent with the fluorescence anisotropy measurements. 相似文献
4.
从目前市场需求和就业率出发,进行形势分析,提出优化专业设置、加强实践环节、提高高职学院办学层次、推进“双证书”制度等改革方法,以促进化工职业教育的发展。 相似文献
5.
Applied Intelligence - Cooperative control is currently a challenging topic of crowded unmanned underwater vehicle (UUV) swarm. However, individual behavior conflict and chain-avalanche collision... 相似文献
6.
Neural Computing and Applications - Nowadays, purchasing the products similar to the styles of stars’ products has become a new trend in e-commerce platforms. Clothing transaction constitutes... 相似文献
7.
单元测试是软件测试过程的第一站,高质量的单元测试是软件质量保证的必要条件,本文就单元测试的概念、测试类型及规程作了简单的阐述,同时就单元测试进行了案例分析。 相似文献
8.
本文通过介绍Applet的体系结构和其生命周期以及如何创建和执行Applet程序,介绍了电子相册的制作过程。 相似文献
9.
随着电力需求量持续增长,220 kV变电站采用双母双分段主接线来提高供电可靠性.在一些停电影响小或负荷不重要的场合,为了节约投资成本,一般都会采用隔离开关进行分段.以某型252 kVGIS为例,提出了一种GIS双母线隔离分段间隔布置结构优化设计型式,从设备尺寸参数、占地面积、元件数量、气体消耗量方面与原布置结构进行经济对比,结果表明优化后布置结构紧凑、占地面积小、元件数量少、气体消耗量少、制造成本和施工成本显著降低,可为其他电压等级的GIS双母线隔离分段间隔布置设计优化提供参考. 相似文献
10.