全文获取类型
收费全文 | 1675篇 |
免费 | 36篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 107篇 |
综合类 | 1篇 |
化学工业 | 448篇 |
金属工艺 | 29篇 |
机械仪表 | 39篇 |
建筑科学 | 25篇 |
矿业工程 | 1篇 |
能源动力 | 72篇 |
轻工业 | 135篇 |
水利工程 | 3篇 |
无线电 | 169篇 |
一般工业技术 | 297篇 |
冶金工业 | 234篇 |
原子能技术 | 40篇 |
自动化技术 | 114篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 22篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 22篇 |
2017年 | 21篇 |
2016年 | 34篇 |
2015年 | 11篇 |
2014年 | 35篇 |
2013年 | 73篇 |
2012年 | 63篇 |
2011年 | 83篇 |
2010年 | 77篇 |
2009年 | 59篇 |
2008年 | 79篇 |
2007年 | 72篇 |
2006年 | 60篇 |
2005年 | 52篇 |
2004年 | 50篇 |
2003年 | 40篇 |
2002年 | 38篇 |
2001年 | 27篇 |
2000年 | 35篇 |
1999年 | 35篇 |
1998年 | 107篇 |
1997年 | 70篇 |
1996年 | 65篇 |
1995年 | 44篇 |
1994年 | 27篇 |
1993年 | 35篇 |
1992年 | 25篇 |
1991年 | 24篇 |
1990年 | 9篇 |
1989年 | 18篇 |
1988年 | 20篇 |
1987年 | 24篇 |
1986年 | 21篇 |
1985年 | 27篇 |
1984年 | 22篇 |
1983年 | 20篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 19篇 |
1979年 | 12篇 |
1978年 | 15篇 |
1977年 | 8篇 |
1976年 | 17篇 |
1975年 | 7篇 |
1974年 | 11篇 |
排序方式: 共有1714条查询结果,搜索用时 23 毫秒
1.
Jun Ogata Kentaro Hirao Kenya Nishioka Arisa Hayashida Yuanzhe Li Hiroyo Yoshino Soichiro Shimizu Nobutaka Hattori Yuzuru Imai 《International journal of molecular sciences》2021,22(7)
Leucine-rich repeat kinase 2 (LRRK2) is a major causative gene of late-onset familial Parkinson’s disease (PD). The suppression of kinase activity is believed to confer neuroprotection, as most pathogenic variants of LRRK2 associated with PD exhibit increased kinase activity. We herein report a novel LRRK2 variant—p.G2294R—located in the WD40 domain, detected through targeted gene-panel screening in a patient with familial PD. The proband showed late-onset Parkinsonism with dysautonomia and a good response to levodopa, without cognitive decline or psychosis. Cultured cell experiments revealed that p.G2294R is highly destabilized at the protein level. The LRRK2 p.G2294R protein expression was upregulated in the patient’s peripheral blood lymphocytes. However, macrophages differentiated from the same peripheral blood showed decreased LRRK2 protein levels. Moreover, our experiment indicated reduced phagocytic activity in the pathogenic yeasts and α-synuclein fibrils. This PD case presents an example wherein the decrease in LRRK2 activity did not act in a neuroprotective manner. Further investigations are needed in order to elucidate the relationship between LRRK2 expression in the central nervous system and the pathogenesis caused by altered LRRK2 activity. 相似文献
2.
3.
In this article, we study a linear array of bowtie nanoantennas placed between two metallic strips that can work from 800 to 1420 nm (600 nm linewidth), with an electric field enhancement factor close to 20. We study the dynamical change of the position of the electric field enhancement amongst different elements in the array and, at the same time, the effects of dispersion on the scalability of the array elements. A systematic analysis and methodology to produce an array that can operate over a large bandwidth whilst maintaining the electric field enhancement without significant variation is provided. 相似文献
4.
Ichiro Hirosawa Tetsuo Honma Kazuo Kato Naoto Kijima Yasuo Shimomura 《Journal of the Society for Information Display》2004,12(3):269-273
Abstract— We studied the influence of annealing in air on doped europium in BaMgAl10O17 by performing x‐ray absorption fine‐structure measurements. We determined the oxidation of doped divalent europium by annealing in air at over 500°C. The interatomic distance between the europium and the surrounding oxygen atoms was compressed by oxidation. It also appears that the oxidation process of europium is determined by the diffusion of oxygen into BaMgAl10O17. 相似文献
5.
6.
The very late antigen-4 (VLA-4) integrin expressed on the surface of lymphocytes and macrophages can regulate their migration to inflammatory sites as well as control cellular activation. The role of VLA-4 in the establishment of autoimmune diabetes is not easily predicted given the multiplicity of adhesion pathways and their differential use by various cell types. The contribution of VLA-4 to insulin-dependent diabetes mellitus was investigated by administration of VLA-4-specific monoclonal antibodies (MoAb) in an adoptive transfer model of disease in NOD mice. This study shows that VLA-4-specific MoAbs profoundly inhibit the development of diabetes with protection sustained by repeated MoAb exposure. Insulitis was completely inhibited during treatment and progressed to a severe degree once MoAb treatment was suspended, yet approximately 40% of treated recipients failed to become diabetic during 1-2 months post-treatment. Although we cannot rule out depletion of a relatively minor subpopulation of cells by prolonged anti-VLA-4 MoAb exposure, this inhibition of diabetes onset by treatment with MoAbs to VLA-4 supports a dependence on VLA-4 for cellular functions leading to diabetes and demonstrates that a significant disease modifying effect can be mediated by targeting the VLA-4 integrin. 相似文献
7.
8.
9.
Yasuo Koide T. Kawakami Masanori Murakami N. Teraguchi Y. Tomomura A. Suzuki 《Journal of Electronic Materials》1998,27(6):772-775
Schottky barrier heights (SBHs) of a variety of metals (In, Cd, Nb, Ti, W, Cu, Ag, Au, Ni, Pt, and Se) contacting to p-ZnSe
grown by a molecular beam epitaxy method were determined by analyzing capacitance-voltage (C-V) and/or current density-voltage
(J-V) curves. The SBH values of the Au and Ni contacts were determined from intersections of straight lines of the C−2-V curves to be 1.23 and 1.13 eV, respectively. The J-V calculations provided a large SBH value of 1.2 ± 0.1 eV for a variety
of metals, indicating that the Fermi-level could be pinned at the contact interface. Reduction of the SBH values to a level
lower than 0.4 eV and/or increase of doping concentrations to a level higher than 1020 cm−3 are essential to obtain an ohmic contact with contact resistivity of around 10−3 Ω·cm2. 相似文献
10.
High performance liquid chromatographic separation of a series of mono-, di- and trihydroxylated 5β-cholanic acids which differ
only in position and configuration of hydroxyl groups at positions C-3, C-7 and/or C-12, is reported. The C-24 free acids
were derivatized to four different classes of UV-sensitive esters, i.e.,p-bromophenacyl (BP),m-methoxyphenacyl (MP), 4-nitrophthalimidemethyl (NPM) and 9-anthrylmethyl (AM) esters, and chromatographed on two, variants
of C18 reversed-phase columns (Nova-Pak C18 and Zorbax ODS) with methanol-water systems as mobile phase. Separation efficiency and elution order of some isomeric pairs
were influenced by both the structure of the C-24 ester groups and the nature of the columns used. Excellent chromatographic
properties were found for those derivatives, particularly for the NPM esters. 相似文献