全文获取类型
收费全文 | 1553篇 |
免费 | 36篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 83篇 |
综合类 | 1篇 |
化学工业 | 334篇 |
金属工艺 | 47篇 |
机械仪表 | 47篇 |
建筑科学 | 36篇 |
能源动力 | 56篇 |
轻工业 | 159篇 |
水利工程 | 6篇 |
石油天然气 | 1篇 |
无线电 | 129篇 |
一般工业技术 | 287篇 |
冶金工业 | 237篇 |
原子能技术 | 62篇 |
自动化技术 | 115篇 |
出版年
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 23篇 |
2020年 | 16篇 |
2019年 | 13篇 |
2018年 | 24篇 |
2017年 | 27篇 |
2016年 | 23篇 |
2015年 | 25篇 |
2014年 | 34篇 |
2013年 | 107篇 |
2012年 | 63篇 |
2011年 | 92篇 |
2010年 | 61篇 |
2009年 | 58篇 |
2008年 | 63篇 |
2007年 | 58篇 |
2006年 | 49篇 |
2005年 | 60篇 |
2004年 | 58篇 |
2003年 | 52篇 |
2002年 | 50篇 |
2001年 | 37篇 |
2000年 | 44篇 |
1999年 | 23篇 |
1998年 | 105篇 |
1997年 | 78篇 |
1996年 | 42篇 |
1995年 | 32篇 |
1994年 | 24篇 |
1993年 | 28篇 |
1992年 | 12篇 |
1991年 | 21篇 |
1990年 | 16篇 |
1989年 | 24篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 7篇 |
1982年 | 17篇 |
1981年 | 9篇 |
1980年 | 4篇 |
1979年 | 9篇 |
1977年 | 14篇 |
1976年 | 14篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1969年 | 3篇 |
排序方式: 共有1600条查询结果,搜索用时 15 毫秒
141.
Atsushi Tsutsumi Hidehiko Suzuki Yasushi Saito Kunio Yoshida Ryohei Yamazaki 《Powder Technology》1998,100(2-3):237-241
The granulation of multi-component particles was conducted in a fast fluidized bed with an atomizing binder solution. The effects of gas velocity and binder droplet diameter on granulation rate, granule size distribution and granule composition were studied. The granulation rate and granule yield were determined by the balance between the agglomeration rate of feed particles and the disintegration rate of granules because there was no secondary granulation. With the increase in gas velocity and the reduction in binder droplet size, the agglomeration rate of feed particles decreased but the disintegration rate of granules increased, resulting in a reduced granule yield. Despite the larger fraction of small particles in the granules, the homogenous granulation of multi-component particles was achieved. 相似文献
142.
Kenta Arima Katsuyoshi Endo Toshihiko Kataoka Kikuji Hirose Hidekazu Goto Yasushi Oshikane Haruyuki Inoue Yoshitaka Tatara Yuzo Mori 《Computational Materials Science》1999,14(1-4):236-240
Local density of states (LDOS) is obtained by the first principles calculation based on the density functional theory on the Si(0 0 1)2 × 1 surface and on the surface with an Al dimer. At an Al dimer, LDOS has a high intensity in the conduction band region, which cannot be seen on the Si(0 0 1)2 × 1 surface. This tendency is observed in STS measurements as well. The possibility for a microelementary analysis is presented by applying this method to other metal atoms on the Si surface. Furthermore, it is pointed out that STS measurements should be always performed at the same tip-sample separation to obtain reproducible STS spectrums. 相似文献
143.
Kawada M. Tungkanawanich A. Kawasaki Z.-I. Matsu-Ura K. 《Power Delivery, IEEE Transactions on》2000,15(2):467-471
Recently, diagnostic techniques have been investigated to detect a partial discharge (PD) associated with a dielectric material defect in a high-voltage electrical apparatus. Gas insulated switchgear (GIS) is an important equipment in a substation, it is highly desirable to measure a partial discharge (PD) occurring in GIS which is a symptom of an insulation breakdown. As it is important to develop a noncontact method for detecting the insulation fault, this paper proposes a new method to detect the wide-band electromagnetic (E-M) wave emitted from PD using the Wavelet transform. The Wavelet transform provides a direct quantitative measure of spectral content, “dynamic spectrum”, in the time-frequency domain. This paper experimentally shows the “dynamic spectrum” of the wide-band E-M wave emitted from PD in the time-frequency domain. This method is shown to be useful for detecting the symptom of the insulation breakdown occurring in GIS 相似文献
144.
Mizuki Tsuta Yasuhiko Sasaki Ikuo Takeuchi Hideki Nakamoto Jun Ishikawa Susumu Kawasaki Junichi Sugiyama Kaori Fujita Masatoshi Yoshimura Mario Shibata Mito Kokawa 《LWT》2014
Flow cytometry (FCM) and aerobic plate count (APC) by the culture method were performed on green tea samples spiked with Escherichia coli type strain NCTC9001 (ATCC11775) solutions of different concentrations. In FCM, fluorescence signals from multiple stained bacteria and other fluorophores are detected using detector channels, and recorded as events with a voltage at each channel. FCM data were analyzed in two ways: conventional and multivariate analysis. In the former, the number of events with voltages larger than the defined threshold values was regarded as the predicted APC. In the latter, voltage histograms of all channels were obtained and merged horizontally to serve as explanatory variables. Then a partial least squares regression (PLSR) model was built to predict APC from the histogram data. The coefficient of determination (R2) and the root mean square error (RMSE) between APC by the culture method and that predicted by conventional FCM were 0.916 and 1.08 cfu/ml2. The APC values predicted by the PLSR model and those measured were in good agreement with R2 of 0.982 and RMSE of 0.417 cfu/ml, which verified the potential of the proposed method for improving APC prediction accuracy by FCM. 相似文献
145.
146.
147.
Hiroaki Ishikawa Takehide Nomura Yasuyuki Saito Haruo Kawasaki Atsushi Okamoto Ryuta Hatakenaka 《亚洲传热研究》2011,40(3):269-285
As heat generation in satellites increases, ensuring that they are provided with sufficient radiator panel area is an important problem. Deployable radiators, with radiator panels that are deployed post‐launch in space to increase the satellite's effective radiator panel area of the satellite, are becoming an important thermal control technology. A reservoir embedded loop heat pipe (RELHP) is used in deployable radiators as a heat transport device. A deployable radiator of this type was mounted on the ETS‐VIII satellite, which was launched on December 18, 2006 and injected into a geostationary orbit. The satellite is still operating without any significant issues over two years later. This paper investigates the heat transport characteristics of an RELHP system used in a deployable radiator in a geostationary orbital environment. This system can be successfully started up in a micro gravity environment. We also found that the sub‐cooling region is shorter in a micro gravity environment than in a terrestrial gravity environment, because there is less heat leakage into the reservoir in a micro gravity environment. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20346 相似文献
148.
Ken Takahashi Yasushi Minagawa Shigeki Yamada Tsunehiro Unno 《Solar Energy Materials & Solar Cells》2001,66(1-4)
Improvement of efficiency of Al0.36Ga0.64As solar cells is advanced in two aspects of minority-carrier lifetime: reduction of majority-carrier concentration in the emitter and base layers, and reduction of deep levels in the back-surface-field (BSF) layer. A pp−n−n structure is proposed to optimize the use of the effect of reduced majority-carrier concentration, and its effectiveness verified in a preparatory experiment on Al0.3Ga0.7As solar cells. A very poor photoluminescence (PL) decay time (below 0.3 ns) of a BSF layer heavily doped with Si becomes 14-fold longer when Se is applied to the dopant instead of Si, resulting in an improvement of the external quantum efficiency near the absorption edge. These two aspects of this study lead to the realization of 16.6% efficiency under 1-sun, AM 1.5 global conditions with an Al0.36Ga0.64As solar cell. 相似文献
149.
150.
We have developed a simultaneous fabrication method using temperature control reactive ion etching (RIE) for channel optical waveguides incorporating plural out-of-plane branching mirrors made from polymer film. By using this method, the etching rate can be adjusted locally by controlling the temperature. This technology also enables the formation of trenches of various depths on the same polymer optical waveguide. We noted from scanning electron microscope (SEM) observations that simultaneous control of the mirror tilt angle and a smooth core surface could be achieved. To be specific, a heat treatment temperature of 130-135°C appears to be the optimum to maintain a rectangular cross section and to achieve a sufficiently smooth core surface for a polymethyl methacrylate (PMMA) waveguide. The measured propagation loss is small, in spite of the presence of a high-Δ waveguide (Δ=5.4%). For example, losses of 0.1, 0.3, and 0.7 dB/cm are measured at wavelengths of 650 nm, 850 nm, and 1.3 μm, respectively. From far-field pattern (FFP) measurements, we found that the mirror plane was almost rectilinear, and that the reflected light can be captured efficiently by a photodiode. In operational temperature tests, we showed that intensity fluctuations of the coupling light can be reduced to less than 1.5 dB for the temperature range between -25°C and +85°C by adopting a sandwich structure with glass plates 相似文献