全文获取类型
收费全文 | 1466篇 |
免费 | 44篇 |
专业分类
电工技术 | 126篇 |
综合类 | 2篇 |
化学工业 | 467篇 |
金属工艺 | 36篇 |
机械仪表 | 52篇 |
建筑科学 | 24篇 |
能源动力 | 88篇 |
轻工业 | 101篇 |
水利工程 | 4篇 |
无线电 | 77篇 |
一般工业技术 | 302篇 |
冶金工业 | 34篇 |
原子能技术 | 56篇 |
自动化技术 | 141篇 |
出版年
2023年 | 14篇 |
2022年 | 22篇 |
2021年 | 30篇 |
2020年 | 15篇 |
2019年 | 18篇 |
2018年 | 23篇 |
2017年 | 21篇 |
2016年 | 47篇 |
2015年 | 22篇 |
2014年 | 36篇 |
2013年 | 104篇 |
2012年 | 89篇 |
2011年 | 83篇 |
2010年 | 84篇 |
2009年 | 82篇 |
2008年 | 77篇 |
2007年 | 72篇 |
2006年 | 72篇 |
2005年 | 54篇 |
2004年 | 46篇 |
2003年 | 46篇 |
2002年 | 44篇 |
2001年 | 26篇 |
2000年 | 20篇 |
1999年 | 25篇 |
1998年 | 29篇 |
1997年 | 29篇 |
1996年 | 25篇 |
1995年 | 21篇 |
1994年 | 19篇 |
1993年 | 19篇 |
1992年 | 11篇 |
1991年 | 15篇 |
1990年 | 19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 | 15篇 |
1982年 | 14篇 |
1981年 | 11篇 |
1980年 | 9篇 |
1979年 | 11篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1971年 | 3篇 |
排序方式: 共有1510条查询结果,搜索用时 0 毫秒
1.
Yoshihiro Yajima 《时间序列分析杂志》1985,6(3):187-201
Abstract. We shall investigate the asymptotic behaviour of the sample autocorrelations and partial autocorrelations of a multiplicative ARIMA process and derive their limiting distributions. Some simulations are presented to illustrate the results obtained. 相似文献
2.
Takeshi Shiofuku Norihiro Abe Yoshihiro Tabuchi Hirokazu Taki Shoujie He 《Artificial Life and Robotics》2008,13(1):290-293
This paper presents an approach of measuring in real-time the vector of finger that is pointing to an object. DSP is used
in the operation processing unit in order to do the real-time processing. The steps include the extraction of flesh-colored
regions from an image, the labeling of the flesh-colored regions, and the detection of two characteristic positions on the
finger so that the direction that the finger is pointing at will be calculated. The entire process takes about 29 msec, which
makes it possible to have the frame rate of 34 fps. With this frame rate, this measurement approach is considered real-time
and promising to be merged into other application systems.
This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January
31–February 2, 2008 相似文献
3.
An effective system control method is presented for applying a three‐phase current‐source PWM converter with a deadbeat controller to active power filters (APFs). In the shunt‐type configuration, the APF is controlled such that the current drawn by the APF from the utility is equal to the current harmonics and reactive current required for the load. To attain the time‐optimal response of the APF supply current, a two‐dimensional deadbeat control scheme is applied to APF current control. Furthermore, in order to cancel both the delay in the two‐dimensional deadbeat control scheme and the delay in DSP control strategy, an Adaptive Line Enhancer (ALE) is introduced in order to predict the desired value three sampling periods ahead. ALE has another function of bringing robustness to the deadbeat control system. Due to the ALE, settling time is made short in a transient state. On the other hand, total harmonic distortion (THD) of source currents can be minimized compared to the case where ideal identification of the controlled system can be made. The experimental results obtained from the DSP‐based APF are also reported. The compensating ability of this APF is very high in accuracy and responsiveness although the modulation frequency is rather low. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(1): 50–61, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20014 相似文献
4.
5.
Oriented poly-p-phenylene sulphide (PPS) films (thickness 12 and 75 m) and PPS powder were carbonized/graphitized after stabilizing by oxidation, in order to examine the effect of sulphur on graphitizability of the resulting carbons. The films and the powder resulted in carbons with a high and a low graphitizability respectively. An in-plane oriented structure of the PPS film was the most predominant factor to lead to a high graphitizability, and sulphur in the precursor did not lower the graphitizability when it was subjected to solid-phase carbonization. These phenomena are discussed on the basis of analytical data. 相似文献
6.
Niobium-germanium films have been deposited on sapphire substrates at 900 C by a chemical transport reaction method. The highest superconducting transition onset temperature T
C,on
of 22.4 K is observed for a nearly stoichiometric Nb3Ge film with the A15-type structure (thickness ~ 93.5 m). Lattice constants for the Nb3Ge phase formed in the Nb-Ge films with both T
C,on
above 22 K and T
C,midpoint
above 21 K are found to extend from 5.143 to 5.153 ». Deposition rates for the obtained films are in the range of 2–10 m/min. Critical current densities for the Nb3Ge film with the highest T
C,on
value are observed to be relatively low (~ 103 A/cm2 at 19 K at self-field). This is due to the coarse grain structure of the film or the low density of effectual pinning centers in the film. Field variations of the pinning forces operating in this film in magnetic fields both parallel to the film surface and perpendicular to the film surface are found to follow closely b
1/2(1\s-b)2, to which the pinning force for flux pinning at the surface of normal regions, such as grain boundaries, film surfaces, etc., is proportional, and where b is the reduced magnetic induction (B/B
C2).A small increase in J
C
at low fields is caused by the presence of a small amount of the Nb5Ge3 phase in a Nb3Ge film, and seems attributable to additional flux pinning on Nb5Ge3-phase particles in the film.Supported by Deutsche Forschungsgemeinschaft. 相似文献
7.
Makoto Kobayashi Masashi Shimada Yuji Hatano Takuji Oda Brad Merrill Yasuhisa Oya Kenji Okuno 《Fusion Engineering and Design》2013,88(9-10):1749-1752
The deuterium trapping behaviors in tungsten damaged by light ions with lower energy (10 keV C+ and 3 keV He+) or a heavy ion with higher energy (2.8 MeV Fe2+) were compared by means of TDS to understand the effects of cascade collisions on deuterium retention in tungsten. By light ion irradiation, most of deuterium was trapped by vacancies, whose retention was almost saturated at the damage level of 0.2 dpa. For the heavy ion irradiation, the deuterium trapping by voids was found, indicating that cascade collisions by the heavy ion irradiation would create the voids in tungsten. Most of deuterium trapped by the voids was desorbed in higher temperature region compared to that trapped by vacancies. It was also found that deuterium could accumulate in the voids, resulting in the formation of blisters in tungsten. 相似文献
8.
Fumiaki Mitsugi Yoshihiro Umeda Norihiro Sakai Tomoaki Ikegami 《Thin solid films》2010,518(22):6334-1307
Recently, transparent conducting oxide thin films have attracted attention for the application to transparent conducting electrodes. In this work, we evaluated the uniformity of electrical, optical and structural properties for gallium doped zinc oxide thin films prepared on the 10 × 10 cm2 silica glass substrate by pulsed laser deposition. The resistivity, carrier concentration, mobility, bonding state and atomic composition of the film were uniform along in-plane and depth direction over the 10 × 10 cm2 area of the substrate. The film showed the average transmittance of 81-87%, resistivity of 1.4 × 10− 3 Ω cm, carrier concentration of 9.7 × 1020/cm3 and mobility of 5 cm2/Vs in spite of the amorphous X-ray diffraction pattern. The gradual thickness distribution was found, however, the potential for large-area and low temperature deposition of transparent conducting oxide thin film using pulsed laser deposition method was confirmed. 相似文献
9.
Riku Kawasaki Kosuke Kondo Risako Miura Keita Yamana Hinata Isozaki Risako Shimada Shogo Kawamura Hidetoshi Hirano Tomoki Nishimura Naoki Tarutani Kiyofumi Katagiri Alexandra Stubelius Shin-ichi Sawada Yoshihiro Sasaki Kazunari Akiyoshi Atsushi Ikeda 《International journal of molecular sciences》2022,23(9)
Developing photoactivatable theranostic platforms with integrated functionalities of biocompatibility, targeting, imaging contrast, and therapy is a promising approach for cancer diagnosis and therapy. Here, we report a theranostic agent based on a hybrid nanoparticle comprising fullerene nanocrystals and gold nanoparticles (FGNPs) for photoacoustic imaging and photothermal therapy. Compared to gold nanoparticles and fullerene crystals, FGNPs exhibited stronger photoacoustic signals and photothermal heating characteristics by irradiating light with an optimal wavelength. Our studies demonstrated that FGNPs could kill cancer cells due to their photothermal heating characteristics in vitro. Moreover, FGNPs that are accumulated in tumor tissue via the enhanced permeation and retention effect can visualize tumor tissue due to their photoacoustic signal in tumor xenograft model mice. The theranostic agent with FGNPs shows promise for cancer therapy. 相似文献
10.
Yoshihiro Konishi Masaki Ishibashi Naoya Baba Eiji Hiraki Mutsuo Nakaoka 《International Journal of Electronics》2013,100(10):1295-1310
This paper presents a novel prototype of three-phase current-fed PWM converter with a switched capacitor type resonant dc link snubber circuit, which can basically operate under a principle of zero current soft switching commutation. The optimum PWM pattern-based control scheme proposed by the authors is effectively applied for this active converter. In this paper, the steady-state operating principle of a new converter circuit treated here is described. The practical design procedure of this converter is discussed from a theoretical point of view. The feasible experiment to confirm zero current soft switching commutation of this converter is concretely implemented and evaluated herein. 相似文献