全文获取类型
收费全文 | 1137篇 |
免费 | 59篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 16篇 |
综合类 | 2篇 |
化学工业 | 325篇 |
金属工艺 | 22篇 |
机械仪表 | 21篇 |
建筑科学 | 44篇 |
矿业工程 | 1篇 |
能源动力 | 19篇 |
轻工业 | 137篇 |
水利工程 | 6篇 |
石油天然气 | 3篇 |
无线电 | 114篇 |
一般工业技术 | 141篇 |
冶金工业 | 195篇 |
原子能技术 | 3篇 |
自动化技术 | 151篇 |
出版年
2023年 | 10篇 |
2022年 | 21篇 |
2021年 | 29篇 |
2020年 | 24篇 |
2019年 | 27篇 |
2018年 | 33篇 |
2017年 | 36篇 |
2016年 | 44篇 |
2015年 | 23篇 |
2014年 | 41篇 |
2013年 | 64篇 |
2012年 | 55篇 |
2011年 | 48篇 |
2010年 | 33篇 |
2009年 | 50篇 |
2008年 | 48篇 |
2007年 | 41篇 |
2006年 | 36篇 |
2005年 | 29篇 |
2004年 | 23篇 |
2003年 | 18篇 |
2002年 | 27篇 |
2001年 | 23篇 |
2000年 | 23篇 |
1999年 | 19篇 |
1998年 | 62篇 |
1997年 | 46篇 |
1996年 | 33篇 |
1995年 | 20篇 |
1994年 | 22篇 |
1993年 | 22篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 11篇 |
1989年 | 16篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 6篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 10篇 |
1975年 | 5篇 |
1969年 | 4篇 |
排序方式: 共有1200条查询结果,搜索用时 0 毫秒
71.
72.
73.
Vicente Pacheco Raul Cardoso-Gil Lorenzo Tepech-Carrillo Yuri Grin 《Corrosion Science》2011,(7):2368-2373
The corrosion of thermoelectric clathrates α- and β-Eu8Ga16−xGe30+x is studied under static air (DSC/TG) up to 650 °C. Oxidation product layers with thicknesses of 10.5 μm (α-Eu8Ga16−xGe30+x) and 4.5 μm (β-Eu8Ga16−xGe30+x) are formed. The oxidation begins at 360 and 380 °C, respectively. XRD pattern of the β-Eu8Ga16−xGe30+x oxidized layer shows Ge and four Eu2O3 reflections; while α-Eu8Ga16−xGe30+x data (sample crushed and grinded) shows α-Eu8Ga16−xGe30+x reflections (majority phase), two EuGa2±xGe4?x strongest reflections and Ge (minority phases). These results indicate the amount of oxides is very small or they are amorphous. High temperature powder XRD measurements on α-Eu8Ga16−xGe30+x under air confirm the oxidation onset temperature determined in DSC studies. 相似文献
74.
商用车涂料为水性聚氨酯涂料拓展更广泛的应用领域 总被引:3,自引:0,他引:3
随着环保重要性的不断增加以及法规压力的不断加大,西欧地区形成了各种低排放交通工具涂料的概念.本文着重介绍了双组分水性聚氨酯体系的应用情况,以及相关的原材料、技术和原理. 相似文献
75.
Raul Rengel Martin M.J. Gonzalez T. Mateos J. Pardo D. Dambrine G. Raskin J.-P. Danneville F. 《Electron Devices, IEEE Transactions on》2006,53(3):523-532
In this paper, a detailed research of the high-frequency noise sources and figures of merit (FOMs) of fabricated deep-submicrometer n-channel fully depleted silicon-on-insulator MOSFETs is carried out. Special care is given to reproduce the main topology parameters, together with the most relevant parasitic elements of real devices in order to accomplish an accurate and reliable simulation. The information provided by the Monte Carlo (MC) tool allows getting a physical insight of the relationship between internal quantities and the main noise sources inside the device; moreover, the spectral density of velocity fluctuations has been analyzed spatially in order to determine the local current noise source in the gradual channel and velocity overshoot sections of the effective channel. Together with the calculation of intrinsic noise sources, the MC simulator is able to reproduce the measurements for the main noise FOMs in the RF and microwave frequency ranges. Moreover, the whole simulation framework allows addressing the importance of parasitic elements in the final value of these FOMs. 相似文献
76.
R. Lyonnet A. Khodan A. Barthe´le´my J.-P. Contour O. Durand J.L. Maurice D. Michel J. Teresa de 《Journal of Electroceramics》2000,4(2-3):369-377
We have studied the pulsed laser deposition (PLD) of Zr1-xCexO2 and Ce1-xLaxO2-x/2 initially to grow buffer layers for perovskite films deposited on Si, LaAlO3, SrTiO3 and MgO and then to produce tunneling barriers for cuprate or manganite heterostructures. On (1 0 0) Si, the deposition of Zr1-xCexO2 (x = 0.12) produces a smooth epitaxial layer (R
RMS = 0.25/1m2), which allows the further deposition of high quality YBa2Cu3O7 (Tc 88 K) and La0.7Sr0.3MnO3 films. On the other hand, the use of Ce1-xLaxO2-x/2 (0 x 0.4) makes it possible to match the YBa2Cu3O7 and La0.7Sr0.3MnO3 layers to various substrates. The buffer layers are epitaxially grown with a 45° rotation of the in-plane axes with respect to those of the substrate, and the smoothness is high (R
RMS = 0.25/1m2). In the case of an ultra-thin barrier (2.5 nm) of Ce1-xLaxO2-x/2 sandwiched in a La0.7Sr0.3MnO3, the out-of-plane mismatch of 2 induces distortions at the interface steps, which propagate into the topmost La0.7Sr0.3MnO3 layer. This is in contrast to the case of SrTiO3 barriers where an ideal crystal continuity in the growth direction is observed. 相似文献
77.
78.
This article offers a critique of assumptions made by both the majority psychoanalytic culture and minority groups regarding the suitability of psychoanalysis for Latinos and other underserved ethnic groups. Both sides of the aforementioned controversy are rooted in the larger conflict between modern and traditional paradigms as well as in the epistemological and political contradictions of the "master's discourse" prevailing within educational institutions. The proposed theory articulates intrapsychic and extrapsychic dimensions into a single theoretical framework. The proposed reconceptualization includes a redefinition of the psychoanalytic concept of insight more in keeping both with the concept of the unconscious and with the conception of knowledge found in traditional cultures. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
79.
A Lafont E Durand F Vilde C Moreyra S Drechsel SS Mirshahi M Mirshahi C Guérot P Lemarchand 《Canadian Metallurgical Quarterly》1998,9(18):2795-2800
Thrombosis represents a major issue during arterial local delivery. We evaluated the occurrence of thrombosis after adenovirus (Ad)-mediated gene transfer into normal and atherosclerotic arteries. A replication-deficient Ad vector expressing the beta-galactosidase reporter gene (Ad.RSV betagal; 4 x 10(9) PFU) was injected into normal and atherosclerotic arteries (n = 11 in both groups). The contralateral artery received either an Ad vector carrying no transgene (Ad.MLPnull) (n = 7 in both groups, 4 x 10(9) PFU) or vehicle buffer (n = 4 in normal group, n = 8 in atherosclerotic group). Animals were sacrificed 3 days following gene transfer for thrombus detection and assessment of beta-galactosidase activity. Thrombus was absent in normal arteries and in atherosclerotic arteries injected with vehicle buffer only. In contrast, nonocclusive thrombus was present in atherosclerotic arteries injected with either Ad.RSV betagal (5 of 11) or Ad.MLPnull (3 of 7). Beta-galactosidase activity was predominantly found in the endothelial layer of the transfected arteries. Gene transfer and expression occurred despite the presence of the thrombus (4 of 5), and its efficiency did not significantly differ regardless of the thrombus. We conclude that thrombus frequently occurred in atherosclerotic arteries after Ad-mediated gene transfer. Further studies are warranted to identify the mechanisms of thrombus generation after Ad-mediated gene transfer into atherosclerotic arteries. 相似文献
80.
In this paper some of the experimental considerations for obtaining phonon attenuation in solids by Brillouin scattering are described. Measurements of room temperature damping of longitudinal hypersonic waves in α-quartz, fused silica, and calcium fluoride are reported. The observed phonon frequency and linewidth for backward scattering of 6328-Å light in these solids is typically ∼ 30 GHz and ∼ 30 MHz (FWHM), respectively. This corresponds to a damping length ofsim 60 mu , which is inaccessible by conventional ultrasonics techniques. 相似文献