全文获取类型
收费全文 | 139820篇 |
免费 | 6750篇 |
国内免费 | 3326篇 |
专业分类
电工技术 | 4583篇 |
技术理论 | 6篇 |
综合类 | 6540篇 |
化学工业 | 20719篇 |
金属工艺 | 7761篇 |
机械仪表 | 6540篇 |
建筑科学 | 6974篇 |
矿业工程 | 2368篇 |
能源动力 | 2930篇 |
轻工业 | 7822篇 |
水利工程 | 2452篇 |
石油天然气 | 3070篇 |
武器工业 | 560篇 |
无线电 | 15879篇 |
一般工业技术 | 22673篇 |
冶金工业 | 5093篇 |
原子能技术 | 929篇 |
自动化技术 | 32997篇 |
出版年
2024年 | 303篇 |
2023年 | 1106篇 |
2022年 | 2016篇 |
2021年 | 2682篇 |
2020年 | 1968篇 |
2019年 | 1676篇 |
2018年 | 16040篇 |
2017年 | 15180篇 |
2016年 | 11587篇 |
2015年 | 3086篇 |
2014年 | 3256篇 |
2013年 | 3734篇 |
2012年 | 7027篇 |
2011年 | 13335篇 |
2010年 | 11970篇 |
2009年 | 9067篇 |
2008年 | 10210篇 |
2007年 | 10785篇 |
2006年 | 3194篇 |
2005年 | 3683篇 |
2004年 | 2871篇 |
2003年 | 2641篇 |
2002年 | 2115篇 |
2001年 | 1479篇 |
2000年 | 1433篇 |
1999年 | 1338篇 |
1998年 | 1002篇 |
1997年 | 845篇 |
1996年 | 810篇 |
1995年 | 602篇 |
1994年 | 545篇 |
1993年 | 372篇 |
1992年 | 342篇 |
1991年 | 256篇 |
1990年 | 178篇 |
1989年 | 156篇 |
1988年 | 109篇 |
1987年 | 67篇 |
1986年 | 54篇 |
1985年 | 37篇 |
1968年 | 43篇 |
1967年 | 35篇 |
1966年 | 44篇 |
1965年 | 44篇 |
1959年 | 39篇 |
1958年 | 37篇 |
1957年 | 36篇 |
1956年 | 34篇 |
1955年 | 63篇 |
1954年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
31.
This paper presents an integrated passive damping approach in hybrid metal-CFRP parts for structural applications. In this concept a viscoelastic material is embedded in the joint zone of the hybrid component. To examine the connection strength single-lap-joint specimens were produced and tested and the influence of the used material combinations, different surface structures, and different process parameters i.e. the moment of cross-linking were evaluated. Afterwards, the metal-CFRP hybrids were tested in quasi-static tests to assess their connection strength and failure behaviour. Dynamic cyclic tensile tests with step-wise increased loading conditions were performed to determine the specimens damping behaviour and to estimate their fatigue performance. Finally, these results are compared to a state of the art metal-CFRP hybrid with rivets connecting both materials. 相似文献
32.
In this paper, we consider the classical finite mixture model, which is an effective tool for modeling lifetime distributions for random samples from heterogeneous populations. We discuss new results on stochastic comparison for two finite mixtures when each of them is drawn from one of the following semiparametric families, i.e., proportional hazards, accelerated lifetime and proportional reversed hazards. 相似文献
33.
34.
35.
Functional expression and synergistic cooperation of xylan‐degrading enzymes from Hypocrea orientalis and Aspergillus niger 下载免费PDF全文
36.
Variations of Incomplete Open Cubes is the major project by the twentieth-century conceptual artist Sol LeWitt. In this paper we interpret the enumerative component of the project as embeddings of graphs. This formulation permits use of an algorithm to check the completeness of the list of the structures produced by the artist. Our conclusion is that the artist found the correct number of structures (that is, 122), but that his list contains a mistake in the presentation of a pair of incomplete cubes, a discovery that appears not to have been noted before. 相似文献
37.
Debin Wang Jingsong Liu Mengshi Zeng Chunmei Zhang Huiqin Li Hongtao Yu Ying Yuan Shuren Zhang 《Journal of the American Ceramic Society》2019,102(7):4029-4037
(1-x)Sr0.7Pb0.15Bi0.1TiO3-xBi4Ti3O12 ((1-x)SPBT-xBIT, x = 0-0.125) bulk ceramics were developed and calcined via the solid-state method, aimed at the application of pulsed power capacitors. The phase structures, temperature stability, hysteresis loop, and discharge properties were systematically investigated. Considering both the temperature stability and dielectric properties, 0.925SPBT-0.075BIT bulk ceramics with a capacitance variation satisfying the X7R specification were developed for pulsed power capacitors. The energy storage density was 0.252 J/cm3, and the ceramics showed high temperature stability at 80 kV/cm. The discharge current waveforms of the 0.925SPBT-0.075BIT ceramics were recorded. A high discharge power density of approximately 1.01 × 108 W/kg with an 8 Ω load resistor and short discharge period of 84 ns were achieved at 50 kV/cm. The good temperature stability properties and high power density show that the 0.925SPBT-0.075BIT ceramics are well suited for pulsed power capacitors with a wide temperature range. 相似文献
38.
Multifunctional 3D Patternable Drug‐Embedded Nanocarrier‐Based Interfaces to Enhance Signal Recording and Reduce Neuron Degeneration in Neural Implantation 下载免费PDF全文
39.
40.
Multimedia Tools and Applications - In Wyner-Ziv (WZ) video coding, decoder side information (SI) takes a key role in a WZ video codec among other building blocks. In this paper, we review the... 相似文献