全文获取类型
收费全文 | 1270篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 66篇 |
综合类 | 1篇 |
化学工业 | 269篇 |
金属工艺 | 29篇 |
机械仪表 | 14篇 |
建筑科学 | 15篇 |
能源动力 | 80篇 |
轻工业 | 75篇 |
水利工程 | 2篇 |
无线电 | 143篇 |
一般工业技术 | 195篇 |
冶金工业 | 303篇 |
原子能技术 | 32篇 |
自动化技术 | 63篇 |
出版年
2022年 | 9篇 |
2021年 | 17篇 |
2020年 | 13篇 |
2019年 | 15篇 |
2018年 | 14篇 |
2017年 | 24篇 |
2016年 | 14篇 |
2015年 | 13篇 |
2014年 | 19篇 |
2013年 | 36篇 |
2012年 | 37篇 |
2011年 | 44篇 |
2010年 | 33篇 |
2009年 | 46篇 |
2008年 | 36篇 |
2007年 | 52篇 |
2006年 | 37篇 |
2005年 | 38篇 |
2004年 | 29篇 |
2003年 | 43篇 |
2002年 | 37篇 |
2001年 | 31篇 |
2000年 | 23篇 |
1999年 | 38篇 |
1998年 | 120篇 |
1997年 | 83篇 |
1996年 | 47篇 |
1995年 | 39篇 |
1994年 | 32篇 |
1993年 | 35篇 |
1992年 | 16篇 |
1991年 | 13篇 |
1990年 | 16篇 |
1989年 | 9篇 |
1988年 | 13篇 |
1987年 | 18篇 |
1986年 | 18篇 |
1985年 | 9篇 |
1984年 | 17篇 |
1983年 | 10篇 |
1982年 | 14篇 |
1981年 | 9篇 |
1980年 | 17篇 |
1979年 | 10篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 13篇 |
1975年 | 3篇 |
1972年 | 5篇 |
1968年 | 3篇 |
排序方式: 共有1287条查询结果,搜索用时 15 毫秒
11.
Using the boundary element method, results of the push-pull ratio of differential output signals from an optical disc pregroove model by simulation are presented. The possibility of achieving higher information density by reducing the track pitch and the beam spot is demonstrated.<> 相似文献
12.
Tomohito Hamazaki Eisuke Takazakura Kenzo Osawa Masaharu Urakaze Saburo Yano 《Lipids》1990,25(9):541-545
Eicosapentaenoic acid (EPA) ethyl ester (1.8 g/d) was administered to 16 diabetic patients (5 insulin-dependent and 11 noninsulin-dependent
diabetics) for 6 mon. EPA in total plasma fatty acids increased from 4.0±2.4 mol% (mean±SD) to 7.5±3.1 mol% (p<0.001). Albumin
excretion, measured with spot urine, was significantly reduced from 65 to 36 mg/g creatinine (geometric means, p<0.001). Fasting
blood sugar levels, glycohemoglobin, body weight and blood pressure did not change significantly during the study. There were
also no significant changes in serum levels of creatinine, urea nitrogen, total cholesterol and triglycerides. Although no
overt hemorrhage was observed in the patients, hematocrit was reduced from 42.6±2.8% to 41.0±3.9% (p<0.02). Ten other similar
diabetic patients (4 insulin-dependent and 6 non-insulin-dependent diabetics) were followed as a reference group, not concomitantly,
for 6 mon with neither EPA ethyl ester nor placebo. The parameters mentioned above were not changed significantly in this
group during 6 mon. EPA administration might retard the appearance of overt diabetic nephropathy. 相似文献
13.
The effects of tensile strain on the swelling behaviour of acrylonitrile-butadiene copolymer rubber vulcanizates were studied by real-time pulsed nuclear magnetic resonance (n.m.r.) measurements and volume swelling measurements at equilibrium. It was shown that tensile strain causes an increase of the initial swelling rate evaluated by n.m.r. measurements and of the swelling ratio of the rubber matrix at equilibrium. This behaviour was discussed qualitatively in terms of the molecular mobility of the network chains on the basis of Treloar's theory for swelling under deformation. It was suggested that the presence of reinforcing fillers in the rubber matrix exerts two noticeable effects on swelling under deformation: (1) a transient effect through some oriented structure induced by stretching, which restricts the increase of the swelling rate; (2) a strain amplification effect, which causes the increase of the average local strain in the rubber matrix and enhances the swelling ratio more remarkably proportional to the filler concentration as compared with that of the unfilled system. 相似文献
14.
Shin D.S. Wang J. Bosch F. Kiely P.A. Chand N. Fischer M. Kojima K. Kasper B.L. Peral E.M. Ransijn H. 《Electronics letters》2002,38(16):864-865
A 1.3 μm uncooled transmitter with wide-open eye diagrams at laser temperatures of 20, 50, and 85°C is presented. Using this transmitter, it is demonstrated that 10 Gbit/s transmission is possible over a 50 km nonzero dispersion-shifted Lucent TrueWave-RS fibre. This result is compared with transmission over a 55 km standard singlemode fibre 相似文献
15.
Takeshi Yanagisawa Takeshi Kojima Tadamasa Koyanagi Kiyoshi Takahisa Kuniomi Nakamura 《Microelectronics Reliability》2002,42(2):219-223
Changes in the characteristics of CuInGaSe2 solar cells in response to light irradiation were investigated. Then these changes, which suggest long-term degradation, were clarified using the measurement technique by feeble light. The thin-film cell of this type is considered to be “ever stable”. A stable result over the short term was also obtained in the light accelerated test of 2-SUN performed in this experiment. On the other hand, it was found that the characteristics measured with feeble light show a remarkable change over time. As a result of measuring at 0.065–105 mW/cm2 light intensity, the change rate of cell output power was so intense the measurement light was weak. This finding reflects the increase in an internal defect and suggests a possibility that light irradiation exerts the influence on long-term cell performance. Moreover, by measuring with feeble light, we found that the changed output recovers by reverse voltage application. The phenomenon of recovery up on comparatively low reverse voltage can be considered as an application for maintaining stability. 相似文献
16.
Kojima T. Miyajima M. Akaboshi F. Yogo T. Ishimoto S. Okuda A. 《Semiconductor Manufacturing, IEEE Transactions on》2000,13(3):293-299
We have developed a chemical mechanical polishing (CMP) process monitor which uses polishing vibration. The monitor enables us to accurately detect the polishing end point in copper (Cu) polishing even when the process conditions such as initial film thickness, slurry flow and polishing rate are changed and when polishing multilayer film. Furthermore, the monitor is not only applicable to Cu polishing but also to planarizing polishing of an inter-level dielectric layer. The monitor can be also used to control the processes and the equipment because of its capability to detect abnormalities in the polishing conditions 相似文献
17.
This paper proposes a hybrid decoupled power flow method for balanced power distribution systems with distributed generation sources.The method formulates the power flow equations in active power and reactive power decoupled form with polar coordinates.Second-order terms are included in the active power mismatch iteration,and constant Jacobian and Hessian matrices are used.A hybrid direct and indirect solution technique is used to achieve efficiency and robustness of the algorithm.Active power correction is solved by means of a sparse lower triangular and upper triangular(LU) decomposition algorithm with partial pivoting,and the reactive power correction is solved by means of restarted generalized minimal residual algorithm with an incomplete LU pre-conditioner.Typical distribution generation models and distribution load models are included.The impact of zero-impedance branches is explicitly modeled through reconfiguring of the adjacent branches with impedances.Numerical examples on a sample distribution system with widespread photovoltaic installations are given to demonstrate the effectiveness of the proposed method. 相似文献
18.
Kan‐Hua Lee Kenji Araki Li Wang Nobuaki Kojima Yoshio Ohshita Masafumi Yamaguchi 《Progress in Photovoltaics: Research and Applications》2016,24(10):1310-1318
The paper presents a quantitative approach to the investigation and comparison of the material qualities of III–V on silicon (III–V/Si) solar cells by using external radiative efficiencies. We use this analysis to predict the limiting efficiencies and evaluate the criteria of material quality in order to achieve high‐efficiency III–V/Si solar cells. This result yields several implications for the design of high‐efficiency III–V/Si solar cells. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
19.
Tomohiro Kasakawa Hiroki Tabata Ryo Onodera Hiroki Kojima Mutsumi Kimura Hiroyuki Hara Satoshi Inoue 《Solid-state electronics》2011,56(1):207-210
We propose degradation evaluation of poly-Si TFTs by comparing normal and reverse characteristics. Since symmetrical normal and reverse characteristics indicate Joule-heating degradation whereas asymmetrical characteristics indicate hot-carrier degradation, they can be clearly and easily classified. Moreover, degradation occurrence is contrasted between standard and fine TFTs. Finally, behavior of the hot-carrier degradation is analyzed. 相似文献
20.
Hara T. Fukuda K. Kanazawa K. Shibata N. Hosono K. Maejima H. Nakagawa M. Abe T. Kojima M. Fujiu M. Takeuchi Y. Amemiya K. Morooka M. Kamei T. Nasu H. Chi-Ming Wang Sakurai K. Tokiwa N. Waki H. Maruyama T. Yoshikawa S. Higashitani M. Pham T.D. Yupin Fong Watanabe T. 《Solid-State Circuits, IEEE Journal of》2006,41(1):161-169
An 8-Gb multi-level NAND Flash memory with 4-level programmed cells has been developed successfully. The cost-effective small chip has been fabricated in 70-nm CMOS technology. To decrease the chip size, a one-sided pad arrangement with compacted core architecture and a block address expansion scheme without block redundancy replacement have been introduced. With these methods, the chip size has been reduced to 146 mm/sup 2/, which is 4.9% smaller than the conventional chip. In terms of performance, the program throughput reaches 6 MB/s at 4-KB page operation, which is significantly faster than previously reported and very competitive with binary Flash memories. This high performance has been achieved by the combination of the multi-level cell (MLC) programming with write caches and with the program voltage compensation technique for neighboring select transistors. The read throughput reaches 60 MB/s using 16I/O configuration. 相似文献