全文获取类型
收费全文 | 406篇 |
免费 | 3篇 |
专业分类
电工技术 | 3篇 |
综合类 | 2篇 |
化学工业 | 102篇 |
金属工艺 | 5篇 |
机械仪表 | 6篇 |
建筑科学 | 10篇 |
矿业工程 | 4篇 |
能源动力 | 14篇 |
轻工业 | 22篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 62篇 |
一般工业技术 | 45篇 |
冶金工业 | 115篇 |
原子能技术 | 1篇 |
自动化技术 | 14篇 |
出版年
2023年 | 3篇 |
2022年 | 17篇 |
2021年 | 12篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2014年 | 8篇 |
2013年 | 16篇 |
2012年 | 11篇 |
2011年 | 8篇 |
2010年 | 15篇 |
2009年 | 7篇 |
2008年 | 23篇 |
2007年 | 8篇 |
2006年 | 15篇 |
2005年 | 7篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 13篇 |
1999年 | 10篇 |
1998年 | 24篇 |
1997年 | 10篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1980年 | 3篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1968年 | 2篇 |
排序方式: 共有409条查询结果,搜索用时 15 毫秒
41.
Halbritter H. Riemenschneider F. Kogel B. Feldmeier E. Meissner P. 《Electronics letters》2004,40(24):1536-1538
A novel idea and realisation of a control algorithm to switch the wavelength of continuously tunable lasers is presented. The concept allows the switching of a defined number of dense wavelength division multiplexed (DWDM) channels up or down by employing a broadband wavelength locker. The switching algorithm is implemented and demonstrated for a micro-electro-mechanically tunable vertical-cavity surface emitting laser (MEM-VCSEL). 相似文献
42.
Internally bypassed star couplers allow bidirectional coherent communication at the same frequency via one subscriber line. For longer subscriber lines the serious limiting factor due to Rayleigh backscattering can be overcome by distributing the star.<> 相似文献
43.
Maute M. Riemenschneider F. Bohm G. Halbritter H. Ortsiefer M. Shau R. Meissner P. Amann M.-C. 《Electronics letters》2004,40(7):430-431
A novel two-chip concept for an electrically pumped and micro-electro-mechanically tunable vertical-cavity surface-emitting laser, with an emission wavelength in the 1.5 /spl mu/m range, is presented. Continuous tuning over 30 nm in singlemode operation has been shown. 相似文献
44.
The therapeutic alliance is often misconceived, misunderstood, or ignored in conceptualizing the therapeutic process and the therapeutic relation in analysis and other forms of therapy. Conversely, I will argue that the alliance is indispensable in all forms of therapy. After briefly outlining the nature of the alliance, I discuss some of the empirical findings regarding its utility in various therapeutic contexts. I then consider its role and function in various therapeutic settings other than adult analysis and psychotherapy, including child analysis, treating various forms of psychopathology, and related contexts like supervision, forensic psychiatry, and hospital and medical treatment. The alliance plays a definite but analogous role in all of these, with differences according to context. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
45.
Identification of Multiple Dityrosine Bonds in Materials Composed of the Drosophila Protein Ultrabithorax
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)
46.
We report on solution‐processed hybrid solar cells consisting of a nanocrystalline inorganic semiconductor, CuInS2, and organic materials. Synthesis of quantized CuInS2 nanoparticles was performed using a colloidal route, where the particle surface was shielded by an organic surfactant. First attempts were made to use nanocrystalline CuInS2 with fullerene derivatives to form flat‐interface donor–acceptor heterojunction solar cells. We investigated also bulk heterojunctions by replacing the CuInS2 single layer by a blend of CuInS2 and p‐type polymer (PEDOT:PSS; poly(3,4‐ethylenedioxythiophene:poly(styrene sulfonic acid) in the same cell configuration. Bulk heterojunction solar cells show better photovoltaic response with external quantum efficiencies up to 20 %. 相似文献
47.
48.
N,N′-Dimethyl perylene tetracarboxylic acid diimide (Me-PTCDI) thin films were prepared by vapor deposition technique. The photogeneration and recombination of singlet and triplet excitons were characterized, utilizing absorption, PL and optically detected magnetic resonance (ODMR) spectroscopy. The results suggest the creation of molecular dimers, which gives rise to the creation of split singlet exciton states and enhancement of population in the triplet exciton state. 相似文献
49.
50.
The functional properties of neuronal tissue critically depend on cellular composition and intercellular comunication. A basic
principle of such communication found in various types of neurons is the generation of action potentials (APs). These APs
depend on the presence of voltage gated ion channels and propagate along cellular processes (e.g. axons) towards target neurons
or other cells. It has already been shown that the properties of ion channels depend on gravity. To discover whether the properties
of APs also depend on gravity, we examined the propagation of APs in earthworms (invertebrates) and isolated nerve fibres
(i.e. bundles of axons) from earthworms under conditions of micro- and macro-gravity. In a second set of experiments we could
verify our results on rat axons (vertebrates). Our experiments carried out during two parabolic flight campaigns revealed
that microgravity slows AP propagation velocity and macrogravity accelerates the transmission of action potentials. The relevance
for live-science related questions is considerable, taking into account that altered gravity conditions might affect AP velocity
in man during space flight missions. 相似文献