全文获取类型
收费全文 | 785篇 |
免费 | 37篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 152篇 |
金属工艺 | 5篇 |
机械仪表 | 5篇 |
建筑科学 | 35篇 |
矿业工程 | 1篇 |
能源动力 | 2篇 |
轻工业 | 45篇 |
水利工程 | 2篇 |
无线电 | 61篇 |
一般工业技术 | 165篇 |
冶金工业 | 106篇 |
原子能技术 | 6篇 |
自动化技术 | 231篇 |
出版年
2023年 | 12篇 |
2022年 | 10篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 21篇 |
2015年 | 23篇 |
2014年 | 32篇 |
2013年 | 53篇 |
2012年 | 32篇 |
2011年 | 30篇 |
2010年 | 32篇 |
2009年 | 22篇 |
2008年 | 34篇 |
2007年 | 34篇 |
2006年 | 21篇 |
2005年 | 32篇 |
2004年 | 31篇 |
2003年 | 11篇 |
2002年 | 15篇 |
2001年 | 16篇 |
2000年 | 22篇 |
1999年 | 23篇 |
1998年 | 54篇 |
1997年 | 34篇 |
1996年 | 27篇 |
1995年 | 17篇 |
1994年 | 9篇 |
1993年 | 13篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 12篇 |
1973年 | 4篇 |
1971年 | 2篇 |
1969年 | 6篇 |
1967年 | 3篇 |
1966年 | 2篇 |
1933年 | 2篇 |
排序方式: 共有822条查询结果,搜索用时 15 毫秒
71.
Numerous recent studies have correlated cuticular hydrocarbon profiles with a wide range of behaviors, particularly in social
insects. These findings are wholly or partly based on multivariate statistical methods such as discriminate analysis (DA)
or principal component analysis (PCA). However, these methods often provide limited insight into the biological processes
that generate the small differences usually detected. This may be a consequence of variability in the system due to inadequate
sample sizes and the assumption that all compounds are independent. A fundamental problem is that these methods combine rather
than separate the effects of signal components. By using cuticular hydrocarbon data from previous social insect studies, we
showed that: (1) in 13 species of Formica ants and seven species of Vespa hornets, at least one group of hydrocarbons in each species was highly (r
2 > 0.8) correlated, indicating that all compounds are not independent; (2) DA was better at group separation that PCA; (3)
the relationships between colonies (chemical distance) were unstable and sensitive to variability in the system; and (4) minor
compounds had a disproportionately large effect on the analysis. All these factors, along with sample size, need to be considered
in the future analysis of complex chemical profiles. 相似文献
72.
73.
74.
W. Seidel P. Colling S. Cooper D. Dummer F. v. Feilitzsch P. Ferger G. Forster M. Frank H. -J. Gebauer J. Igalson E. Kellner U. Nagel A. Nucciotti F. Pröbst A. Rulofs L. Stodolsky 《Journal of Low Temperature Physics》1993,93(3-4):797-802
We plan a dark matter search using cryogenic calorimetric detectors with superconducting phase transition thermometers. We discuss such an experiment, compare its estimated sensitivity range with other dark matter searches, and discuss its planned realization. 相似文献
75.
76.
77.
78.
Batteries: Carbon‐Based Anodes for Lithium Sulfur Full Cells with High Cycle Stability (Adv. Funct. Mater. 9/2014)
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
79.
Jan Brückner Sören Thieme Falko Böttger‐Hiller Ingolf Bauer Hannah Tamara Grossmann Patrick Strubel Holger Althues Stefan Spange Stefan Kaskel 《Advanced functional materials》2014,24(9):1284-1289
The lithium sulfur battery system has been studied since the late 1970s and has seen renewed interest in recent years. However, even after three decades of intensive research, prolonged cycling can only be achieved when a large excess of electrolyte and lithium is used. Here, for the first time, a balanced and stable lithium sulfur full cell is demonstrated with silicon–carbon as well as all‐carbon anodes. More than 1000 cycles, a specific capacity up to 1470 mAh g?1 sulfur (720 mAh g?1 cathode), and a high coulombic efficiency of over 99% even with a low amount of electrolyte are achieved. The alternative anodes do not suffer from electrolyte depletion, which is found to be the main cause of cell failure when using metallic lithium anodes. 相似文献