全文获取类型
收费全文 | 1315篇 |
免费 | 42篇 |
专业分类
电工技术 | 138篇 |
综合类 | 2篇 |
化学工业 | 375篇 |
金属工艺 | 32篇 |
机械仪表 | 49篇 |
建筑科学 | 24篇 |
能源动力 | 91篇 |
轻工业 | 107篇 |
水利工程 | 2篇 |
无线电 | 72篇 |
一般工业技术 | 278篇 |
冶金工业 | 39篇 |
原子能技术 | 41篇 |
自动化技术 | 107篇 |
出版年
2023年 | 7篇 |
2022年 | 13篇 |
2021年 | 26篇 |
2020年 | 13篇 |
2019年 | 14篇 |
2018年 | 21篇 |
2017年 | 14篇 |
2016年 | 47篇 |
2015年 | 21篇 |
2014年 | 35篇 |
2013年 | 92篇 |
2012年 | 77篇 |
2011年 | 76篇 |
2010年 | 77篇 |
2009年 | 66篇 |
2008年 | 69篇 |
2007年 | 64篇 |
2006年 | 63篇 |
2005年 | 55篇 |
2004年 | 46篇 |
2003年 | 41篇 |
2002年 | 41篇 |
2001年 | 24篇 |
2000年 | 19篇 |
1999年 | 24篇 |
1998年 | 29篇 |
1997年 | 27篇 |
1996年 | 21篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 16篇 |
1992年 | 11篇 |
1991年 | 12篇 |
1990年 | 17篇 |
1989年 | 15篇 |
1988年 | 5篇 |
1987年 | 15篇 |
1986年 | 10篇 |
1985年 | 9篇 |
1984年 | 13篇 |
1983年 | 14篇 |
1982年 | 14篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有1357条查询结果,搜索用时 15 毫秒
91.
A laser-induced breakdown spectroscopy (LIBS) technique has been applied for detection of unburned carbon in fly ash, and an automated LIBS unit has been developed and applied in a 1000-MW pulverized-coal-fired power plant for real-time measurement, specifically of unburned carbon in fly ash. Good agreement was found between measurement results from the LIBS method and those from the conventional method (Japanese Industrial Standard 8815), with a standard deviation of 0.27%. This result confirms that the measurement of unburned carbon in fly ash by use of LIBS is sufficiently accurate for boiler control. Measurements taken by this apparatus were also integrated into a boiler-control system with the objective of achieving optimal and stable combustion. By control of the rotating speed of a mill rotary separator relative to measured unburned-carbon content, it has been demonstrated that boiler control is possible in an optimized manner by use of the value of the unburned-carbon content of fly ash. 相似文献
92.
Uzawa H Nishida Y Sasaki K Minoura N Kobayashi K 《Chembiochem : a European journal of chemical biology》2003,4(7):640-647
The substrate specificities of three molluscan sulfatases (E.C. 3.1.6.1; snail, abalone, and limpet origins) were investigated with assorted p-nitrophenyl (pNP) di-O-sulfonated beta-D-galactopyranosides and beta-lactosides [3,6-SO(3) Gal (1), 3',6'-SO(3) Lac (2), 4, 6SO(3) Gal (3), 2,6-SO(3) Gal (4), 3,4-SO(3) Gal (5), and 3,6-SO(3) GalNAc (6); Ac, acetyl; Gal, galactose; Lac, lactose] together with mono-O-sulfonated beta-D-galactopyranoside [pNP 3SO(3)-Gal (7)] and tri-O-sulfonated alpha-D-galactopyranoside [2,3,6-SO(3)-alpha-Gal (11)]. Some notable differences between the substrate specificity of the three sulfatases were disclosed; snail sulfatase hydrolyzed the 3O- and 2O-sulfo groups of 1 and 4, respectively, to afford 6SO(3) Gal (9) in high yields, while the abalone enzyme did not act on 4. Only the limpet enzyme could cleave the 3O-sulfo groups of 7 to give pNP beta-galactoside. In contrast, every enzyme could utilize 11 as a good substrate to afford a mixture of 6SO(3)-alpha-Gal (13) and 2,6-SO(3) alpha-Gal (12). None of the enzymes could cleave the O-sulfo groups of 5 and 6, which indicates that a primary 6O-sulfo group tends to promote the enzymatic hydrolysis of O-sulfo groups at the secondary positions. 相似文献
93.
Yoshihiro Kato Author Vitae Teruaki Hirano Author Vitae Author Vitae 《Pattern recognition》2007,40(6):1646-1659
A new matching algorithm for contour images described by chain coded expression is presented. In our face authentication system, the isodensity contours has been introduced to differentiate between the facial features. These isodensity contours can be transformed into chain codes. By using these coded isodensity contours, remarkable improvement in the processing performance can be expected in terms of the processing time and memory requirements.From the computer simulation performed using images of 50 people, it turned out clear that the processing time was decreased to approximately one-seventh compared to the conventional method. With respect to memory requirement, it was reduced to a quarter. 相似文献
94.
Hiroyuki Moriuchi Yoshihiro Tadokoro Masahide Sato Takeshi Furusawa Noboru Suzuki 《Journal of Electronic Materials》2007,36(3):220-225
Lead-free commercial products have been dramatically increasing in the world markets as the restriction of certain hazardous
substances (RoHS) directive in the European Union has been enacted. At the same time, the problem of “tin whiskers” has become
one of the most serious problems in the industry. Growth of tin whiskers is believed to be related to residual stress inside
the tin plating film and external compressive stress. Whiskers in fine-pitch connectors have affected the practical production
of advanced digital equipment. The Japan Electronics and Information Technology Industries Association (JEITA) has proposed
a new testing method to evaluate tin whiskers, especially for the fine-pitch connectors. This paper describes the microstructures
of external stress whiskers and the mechanical indentation test method. 相似文献
95.
Yoshihiro Kanno 《Optimization and Engineering》2016,17(4):861-896
It is classical that, when the small deformation is assumed, the incremental analysis problem of an elastoplastic structure with a piecewise-linear yield condition and a linear strain hardening model can be formulated as a convex quadratic programming problem. Alternatively, this paper presents a different formulation, an unconstrained nonsmooth convex optimization problem, and proposes to solve it with an accelerated gradient-like method. Specifically, we adopt an accelerated proximal gradient method, that has been developed for a regularized least squares problem. Numerical experiments show that the presented algorithm is effective for large-scale elastoplastic analysis. Also, a simple warm-start strategy can speed up the algorithm when the path-dependent incremental analysis is carried out. 相似文献
96.
Yoshihiro Maruyama Takumi Hamaguchi Tien-Hsiu Tsai 《Journal of Nuclear Science and Technology》2018,55(2):199-208
A new ‘transXend’ detector system has been developed for energy-resolved computed tomography (CT). It consists of several segmented detectors that measure X-rays as electric currents. Response functions of segmented detectors are estimated using component materials of a body under inspection to unfold X-ray spectra. To avoid material-dependent measurements, response functions inherent to segmented detectors are evaluated by Monte Carlo calculations. CT was performed for a phantom consisting of five resins and was analyzed by the estimated response functions. The linear attenuation coefficients for the five resins have excellent agreement with database values. 相似文献
97.
Amorphous and crystallized poly(L -lactic acid) (PLLA) films were prepared and the hydrolytic degradation of the ultraviolet (UV)-treated and UV-nontreated films was investigated. This study reveals that the combination of UV and thermal treatments can produce the PLLA materials having different hydrolytic degradation profiles and that the UV-irradiation in the environment will affect the design of recycling process for PLLA articles. In an early stage, the degrees of hydrolytic degradation monitored by weight loss (Wloss), number-average molecular weight (M n), and melting temperature (T m) were higher for the UV-treated films than for the UV-nontreated films. In a late stage, the trend traced by Wloss was reversed, and the difference in the degrees of hydrolytic degradation between the UV-treated and UV-nontreated films monitored by M n and T m became smaller, with the exception of the degrees of hydrolytic degradation of the amorphous films traced by T m. Also, in the early stage, the degrees of hydrolytic degradation monitored by Wloss and M n were higher for the crystallized films than for the amorphous films. In the late stage, this trend was reversed, with the exception of the degrees of hydrolytic degradation of the UV-treated films monitored by M n. The main factors that determined the Wloss and T m were the molecular weight and initial crystallinty but not the molecular structures such as terminal CC double bonds and crosslinks. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
98.
D. Saito Y. Ito K. Hanai T. Kobayashi N. Imanishi A. Hirano Y. Takeda O. Yamamoto 《Journal of power sources》2010,195(18):6172-6176
A spherical carbon material of meso-carbon microbead (MCMB) was examined as an anode in a polyethylene oxide (PEO) based polymer electrolyte lithium battery. The electrochemical performance of the carbon electrode with the polymer electrolyte depended on the electrode thickness and the particle size of MCMB. The 30 μm-thick electrode of MCMB with the particle size of 20–30 μm showed a reversible capacity comparable with that in a liquid electrolyte, but the 100 μm-thick electrode showed a half of the 30 μm-thick electrode. The smaller particle size of 5–8 μm exhibited a high irreversible capacity at the first charge–discharge cycle. The reaction heat between MCMB and the polymer electrolyte was 0.5 J mAh?1, which was much lower compared to those between lithium metal and the polymer electrolyte, 1.2 J mAh?1, and MCMB and conventional liquid electrolyte, 4.3 J mAh?1. 相似文献
99.
Kholid Akhmad Hiroaki Okamoto Akio Kitamura Hiromu Matsuda Fumio Yamamoto Yoshihiro Hamakawa 《Solar Energy Materials & Solar Cells》1997,47(1-4)
The experiments investigated phenomena related to direct contact between the DC output of a PV array and the AC power from the utility grid. The results show that the DC power flows through the distribution transformers (DC-injection) saturating their magnetic circuits. The saturation of magnetic circuits makes peak currents, incorporating a large portion of even harmonics, flow through the high-voltage side of the distribution transformer, adding the level of harmonic distortion of its exciting current. With the increase of injecting DC-current to the utility grid, peak currents at the primary side of distribution transformer increases the most, and even among the same effective (rms) values, the increase of primary side current is larger than that of the secondary side current. 相似文献
100.
Yoshihiro Imai Tadashi Tokumasu Hidehiro Nagamura Kiyoshi Miyaike Hisakazu Matsumoto Hiroshi Hasegawa Hiroshi Kusafuka Masatoyo Shibuya Ryukichi Takahashi 《Electrical Engineering in Japan》2007,160(2):30-38
In the combined‐cycle power plant generators are started by using the igniting arrangement up to the ignition rotational speed of the gas turbine. On the other hand, in the case of using the superconducting generator, it is difficult to apply the igniting arrangement used to generate electricity on the combined cycle for the structure as is. We examined the induction motor starting method for the superconducting generator by using the 70‐MW‐class quick‐response excitation superconducting model generator and the VVVF power supply. From the examination, we confirmed the ability to raise the rotational speed from 6 to 360 rpm. Moreover, it was found to be able to start 200‐MW‐class superconducting generators by the induction motor starting method with the analysis. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(2): 30– 38, 2007; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20283 相似文献