全文获取类型
收费全文 | 922篇 |
免费 | 35篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 55篇 |
化学工业 | 303篇 |
金属工艺 | 18篇 |
机械仪表 | 20篇 |
建筑科学 | 15篇 |
能源动力 | 58篇 |
轻工业 | 88篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 51篇 |
一般工业技术 | 173篇 |
冶金工业 | 66篇 |
原子能技术 | 33篇 |
自动化技术 | 74篇 |
出版年
2024年 | 2篇 |
2023年 | 10篇 |
2022年 | 36篇 |
2021年 | 33篇 |
2020年 | 18篇 |
2019年 | 26篇 |
2018年 | 27篇 |
2017年 | 27篇 |
2016年 | 35篇 |
2015年 | 20篇 |
2014年 | 52篇 |
2013年 | 74篇 |
2012年 | 68篇 |
2011年 | 61篇 |
2010年 | 52篇 |
2009年 | 51篇 |
2008年 | 55篇 |
2007年 | 41篇 |
2006年 | 37篇 |
2005年 | 27篇 |
2004年 | 25篇 |
2003年 | 28篇 |
2002年 | 19篇 |
2001年 | 14篇 |
2000年 | 12篇 |
1999年 | 5篇 |
1998年 | 23篇 |
1997年 | 12篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有960条查询结果,搜索用时 15 毫秒
31.
中国液态锂铅包层材料研究进展 总被引:2,自引:0,他引:2
黄群英 李春京 李艳芬 刘少军 宋勇 彭蕾 章毛连 朱志强 高胜 郭智慧 王永亮 吴宜灿 周新贵 万发荣 单以银 郁金南 朱升云 张品源 杨建锋 李合琴 巨新 室贺健夫 长坂琢也 大贯惣明 FDS团队 《原子能科学技术》2007,41(Z1):397-406
液态锂铅包层是国际上普遍关注和最有发展潜力的聚变堆包层概念设计之一,而包层材料是液态锂铅包层的核心问题之一.目前,液态锂铅包层普遍选用低活化铁素体/马氏体钢(RAFM钢)作为结构材料,液态锂铅作为中子倍增剂及氚增殖剂.另外,部分设计采用了耐高温、电绝缘流道插件作为功能材料,以降低磁流体动力学效应及提高冷却剂出口温度(高于700℃).为适应液态包层的发展需求,中国科学院等离子体物理研究所FDS团队联合国内外相关研究单位,进行了具有中国自主知识产权的中国低活化马氏体钢(CLAM钢)及液态锂铅包层功能材料研发,并开展了锂铅热对流及强迫对流回路的设计、研制及腐蚀实验研究,以研究液态金属锂铅的流动特性及其与结构和功能材料的相容性.同时建立了聚变堆材料数据库平台,为促进中国聚变堆液态包层及材料技术的研究和发展提供数据支持. 相似文献
32.
Shuji Fukahori Hideaki Ichiura Takuya Kitaoka Hiroo Tanaka Hiroyuki Wariishi 《Journal of Materials Science》2007,42(15):6087-6092
Titanium dioxide (TiO2) powder-containing sheet composites, called TiO2 sheet, were prepared by a papermaking technique, and their photocatalytic efficiency was investigated. The TiO2 powders were homogeneously scattered over the fiber-mix networks tailored within the catalyst sheet. Under UV irradiation,
the TiO2 paper could decompose p-hydroxyacetophenone (p-HAP), although the degradation efficiency by the TiO2 sheet was lower than that by the TiO2 powder. Scanning electron microscopy revealed that coverage of the TiO2 particles inside the sheet by alumina binder which was used to improve the sheet strength caused the deterioration of the
photocatalytic performance. Internal addition of alumina binder made the TiO2 sheet porous and such a TiO2 sheet exhibited high photocatalytic performance equivalent to that of TiO2 powder. The porous structure of TiO2 sheet might contribute to effective transport of p-HAP to the surface of TiO2 particles inside the sheet, resulting in high degradation performance. In addition, TiO2 sheet prepared using TiO2 sol showed higher photocatalytic efficiency than TiO2 powder and it was indicated that the porous sheet structure might provide suitable conditions for TiO2 catalysis for photodecomposition. 相似文献
33.
Minami Takuya; Wampold Bruce E.; Serlin Ronald C.; Kircher John C.; Brown George S. 《Canadian Metallurgical Quarterly》2007,75(2):232
This study estimates pretreatment-posttreatment effect size benchmarks for the treatment of major depression in adults that may be useful in evaluating psychotherapy effectiveness in clinical practice. Treatment efficacy benchmarks for major depression were derived for 3 different types of outcome measures: the Hamilton Rating Scale for Depression (M. A. Hamilton, 1960, 1967), the Beck Depression Inventory (A. T. Beck, 1978; A. T. Beck & R. A. Steer, 1987), and an aggregation of low reactivity-low specificity measures. These benchmarks were further refined for 3 conditions: treatment completers, intent-to-treat samples, and natural history (wait-list) conditions. The study confirmed significant effects of outcome measure reactivity and specificity on the pretreatment-posttreatment effect sizes. The authors provide practical guidance in using these benchmarks to assess treatment effectiveness in clinical settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
34.
Takuya Otani Kenji Hashimoto Takaya Isomichi Akira Natsuhara Masanori Sakaguchi Yasuo Kawakami 《Advanced Robotics》2013,27(22):1197-1206
In previous studies, various stabilizing control methods for humanoids during the stance phase while hopping and running were proposed. Although these methods contribute to stability while hopping and running, it is possibility that the control during the flight phase could also affect the stability. In this study, we investigated whether the control during the flight phase can affect the stability of a humanoid while running. To achieve stable hopping, we developed a control system that accounts for the angular momentum of the whole body during the flight phase. In this system, the angular momentum generated by the motion of the lower body in each time interval is calculated during the flight phase, and the trunk joints are controlled to generate the angular momentum necessary to compensate for the deviation of the waist posture, which is used as the reference point for the motion coordinate system of the robot. Once the proposed control system was developed and simulated, we found that the hopping duration in the unconstrained state was extended. 相似文献
35.
Marc Delcroix Keisuke Kinoshita Tomohiro Nakatani Shoko Araki Atsunori Ogawa Takaaki Hori Shinji Watanabe Masakiyo Fujimoto Takuya Yoshioka Takanobu Oba Yotaro Kubo Mehrez Souden Seong-Jun Hahm Atsushi Nakamura 《Computer Speech and Language》2013,27(3):851-873
Research on noise robust speech recognition has mainly focused on dealing with relatively stationary noise that may differ from the noise conditions in most living environments. In this paper, we introduce a recognition system that can recognize speech in the presence of multiple rapidly time-varying noise sources as found in a typical family living room. To deal with such severe noise conditions, our recognition system exploits all available information about speech and noise; that is spatial (directional), spectral and temporal information. This is realized with a model-based speech enhancement pre-processor, which consists of two complementary elements, a multi-channel speech–noise separation method that exploits spatial and spectral information, followed by a single channel enhancement algorithm that uses the long-term temporal characteristics of speech obtained from clean speech examples. Moreover, to compensate for any mismatch that may remain between the enhanced speech and the acoustic model, our system employs an adaptation technique that combines conventional maximum likelihood linear regression with the dynamic adaptive compensation of the variance of the Gaussians of the acoustic model. Our proposed system approaches human performance levels by greatly improving the audible quality of speech and substantially improving the keyword recognition accuracy. 相似文献
36.
Hagiwara M Takahashi S Hoshina T Takeda H Tsurumi T 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(9):1721-1729
The electric transient response method is an effective technique to evaluate material constants of piezoelectric ceramics under high-power driving. In this study, we tried to incorporate nonlinear piezoelectric behaviors in the analysis of transient responses. As a base for handling the nonlinear piezoelectric responses, we proposed an assumption that the electric displacement is proportional to the strain without phase lag, which could be described by a real and constant piezoelectric e-coefficient. Piezoelectric constitutive equations including nonlinear responses were proposed to calculate transient responses of a piezoelectric resonator. The envelopes and waveforms of current and vibration velocity in transient responses observed in some piezoelectric ceramics could be fitted with the calculation including nonlinear responses. The procedure for calculation of mechanical quality factor Q(m) for piezoelectric resonators with nonlinear behaviors was also proposed. 相似文献
38.
Kenji Goto Takuya Kawashima Nobuo Tanabe 《Solar Energy Materials & Solar Cells》2006,90(18-19):3251-3260
We developed new heat-resisting transparent conductive oxide (TCO) films with resistivity of 1.4×10−4 Ω cm, an optical transmittance of above 80% (at 550 nm) and heat-resisting temperature at above 600 °C. The TCO films consists of fluorine-doped tin oxide films coated on indium–tin oxide films. They were prepared by a spray pyrolysis deposition method on glass substrates. The 100×100 mm2 dye-sensitized solar cells (DSCs) were prepared with the TCO films. An energy conversion efficiency of the DSC was improved drastically in comparison to the case with conventional TCO films. 相似文献
39.
Atsushi Watarai Keigo Kubota Masaki Yamagata Takuya Goto Toshiyuki Nohira Rika Hagiwara Koichi Ui Naoaki Kumagai 《Journal of power sources》2008,183(2):724-729
The physicochemical properties of molten alkali bis(trifluoromethylsulfonyl)amide, MTFSI (M = Li, K, Cs), mixture (xLiTFSI = 0.20, xKTFSI = 0.10, xCsTFSI = 0.70) were studied to develop a new rechargeable lithium battery operating at intermediate temperature (100–180 °C). The viscosity and ionic conductivity of this melt at 150 °C are 87.2 cP and 14.2 mS cm−1, respectively. The cyclic voltammetry revealed that the electrochemical window at 150 °C is as wide as 5.0 V, and that the electrochemical deposition/dissolution of lithium metal occurs at the cathode limit. A Li/MTFSI (M = Li, K, Cs)/LiFePO4 cell showed an excellent cycle performance at a constant current rate of C/10 at 150 °C; 95% of the initial discharge capacity was maintained after 50 cycles. Except for the initial few cycles, the coulombic efficiencies were approximately 100% for all the cycles, indicating the stabilities of the molten MTFSI mixture and all the electrode materials. 相似文献
40.
H Shimada K Nakajima T Ochiai Y Koide SI Okazumi H Matsubara A Takeda Y Miyazawa M Arima K Isono 《Canadian Metallurgical Quarterly》1998,5(4):871-874
The significance of serum p53-Abs in patients with esophageal squamous cell carcinoma was determined. Examination of clinicopathological features and assessment of tumor marker sensitivities of carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC-Ag) and CYFRA21-1 were performed. Thirty-three (58%) of 57 patients were positive for serum p53-Abs, however, no relation with cancer progression existed. Fourteen of the 33 sero-positive patients revealed normal levels of all tumor markers tested. Thus, serum p53-Abs appears to be a useful marker for the detection of esophageal squamous cell carcinoma. 相似文献