全文获取类型
收费全文 | 1991篇 |
免费 | 32篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 76篇 |
综合类 | 2篇 |
化学工业 | 514篇 |
金属工艺 | 58篇 |
机械仪表 | 43篇 |
建筑科学 | 19篇 |
能源动力 | 74篇 |
轻工业 | 101篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 271篇 |
一般工业技术 | 326篇 |
冶金工业 | 314篇 |
原子能技术 | 89篇 |
自动化技术 | 136篇 |
出版年
2023年 | 6篇 |
2022年 | 18篇 |
2021年 | 26篇 |
2020年 | 13篇 |
2019年 | 20篇 |
2018年 | 24篇 |
2017年 | 14篇 |
2016年 | 27篇 |
2015年 | 31篇 |
2014年 | 38篇 |
2013年 | 93篇 |
2012年 | 63篇 |
2011年 | 102篇 |
2010年 | 64篇 |
2009年 | 72篇 |
2008年 | 89篇 |
2007年 | 69篇 |
2006年 | 73篇 |
2005年 | 61篇 |
2004年 | 65篇 |
2003年 | 78篇 |
2002年 | 55篇 |
2001年 | 51篇 |
2000年 | 49篇 |
1999年 | 56篇 |
1998年 | 138篇 |
1997年 | 77篇 |
1996年 | 67篇 |
1995年 | 58篇 |
1994年 | 48篇 |
1993年 | 42篇 |
1992年 | 34篇 |
1991年 | 29篇 |
1990年 | 27篇 |
1989年 | 21篇 |
1988年 | 22篇 |
1987年 | 19篇 |
1986年 | 16篇 |
1985年 | 27篇 |
1984年 | 21篇 |
1983年 | 18篇 |
1982年 | 18篇 |
1981年 | 18篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1978年 | 9篇 |
1977年 | 16篇 |
1976年 | 10篇 |
1967年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有2027条查询结果,搜索用时 15 毫秒
101.
T. Arai S. Onari K. Matsuishi H. Yasuoka 《Journal of Infrared, Millimeter and Terahertz Waves》1984,5(12):1581-1587
Far infrared reflection, Raman, and Brillouin spectra of amorphous semiconductor As?S systems are measured. From the reflection spectra, the optical constants are calculatured by the Kramers Kronig analysis. The existence of some intermediate range interaction among molecular units AsS3 is suggested. From the analysis of the Boson peak at low frequency region in Raman scattering, the correlation length is obtained to be ca. 6 Å. From the absorption coefficient in the low frequency region about 3% fluctuation of charge is suggested for As2S3 by schlömann theory. 相似文献
102.
Nakamura Masahiko Suzuki Yutaka Nagasawa Touru Sugihara Masami Takahashi Takashi 《IEEE transactions on bio-medical engineering》1982,(3):192-201
The homomorphic filtering method is described for the detection and quantitation of left-to-right shunts from radionuclide angiocardiography. First, the method is investigated theoreticatly and numerically using a realistic model with systemic recirculation. It is demonstrated that even in a noisy situation the shunt flow fraction can be relatively well estimated, if only the characteristics of the fiters used are suitable. Second, the method is applied to real data, i.e., the pulmonary time-activity curves from radionucUde anglocardiography. The presence or absence of a left-to-right shunt is determined using the ratio AT/MTT. The pulmonary-to-systemic flow ratios calculated from the areas of the two decomposed curves are compared with those from oximetry at cardiac catheterization. Good agreement between the Qp/Qs ratios calculated by oximetry and radionucUide angiocardiography is obtained. 相似文献
103.
Nakamura Masahiko Suzuki Yutaka Tomoda Haruo 《IEEE transactions on bio-medical engineering》1982,(7):523-530
A quantitative approach for correction of background counts is described for determination of the left ventricular ejection fraction from first-pass radionuclide angiocardiography. First, the method is investigated theoretically and numerically using a mathematical model. It is demonstrated that the ejection fraction can be estimated relatively well, even in a noisy situation. Second, the method is applied to the left ventricular time-activity curves from two different regions of interest, the carefully selected and the laxly selected, and these are compared to each other. Good agreement (correlation coefficient = 0.96) for 20 patients was obtained between the ejection fractions from the carefully selected region of interest and those from the laxly selected one. 相似文献
104.
Shahira Said Aly Tsuyoshi Imai Mohamed Salah Hassouna Diem-Mai Kim Nguyen Takaya Higuchi Ariyo Kanno Koichi Yamamoto Rinji Akada Masahiko Sekine 《International Journal of Hydrogen Energy》2018,43(10):5300-5313
The ability of Clostridium butyricum RAK25832 to use casamino acids as a nitrogen source was investigated. Strain RAK25832 showed the capacity to utilize different types of carbon sources. With glucose as a carbon source (10 g/L), the preferred final concentration of casamino acids was 26.67 g/L, with a cumulative hydrogen production, production rate, and yield of 2505 mL H2/L, 160 mL/h, and 1.81 mol H2/mol glucose, respectively. Eighteen metal elements were screened to identify the most important metals for biohydrogen production, and four elements were optimized. The optimal medium composition was MgCl2·6H2O (0.1 g/L), K2HPO4·3H2O (6.67 g/L), NaHCO3 (2.6 g/L), and FeCl2·4H2O (0.002 g/L). Vitamin supplementation of the medium showed no significant effect on hydrogen production. Under the optimized conditions, cumulative hydrogen production reached 3074 mL H2/L. This is the first study to demonstrate the use of casamino acids as a nitrogen source by C. butyricum. 相似文献
105.
106.
Characterization of electrical properties and photosensitivity of SnS thin films prepared by the electrochemical deposition method 总被引:2,自引:0,他引:2
Naoya Sato Masaya Ichimura Eisuke Arai Yoshihisa Yamazaki 《Solar Energy Materials & Solar Cells》2005,85(2):153-165
Using the electrochemical deposition (ECD) method, we prepared tin sulfide thin films, which are suitable for the absorption layer in solar cells because of its bandgap energy (1 eV). We first optimized pulse-form biasing for ECD by characterizing deposited samples with scanning electron microscope, Auger electron spectroscopy and X-ray diffraction measurements. Then, we investigated the electrical properties of deposited SnS thin films and the properties of contacts with several different metals. Furthermore, we observed the photoconductivity of the films by means of photoelectrochemical measurements. From these results, we confirmed that the SnS thin films show p-type conduction. 相似文献
107.
Yi Liu Toyoki Fujiwara Hiroshi Yukawa Masahiko Morinaga 《Solar Energy Materials & Solar Cells》2000,62(1-2)
Employing the DV-Xα molecular orbital method, lithium intercalation effect and alloying effect have been investigated on the electronic structures of spinel MxMn2−xO4 and LiMxMn2−xO4 (M=Ti, V, Cr, Mn, Fe, Co, Ni and Cu). It is found that the lithium intercalation induces the electron transfer from Li to the surrounding O ions, and enlarges the Mn-3d/O-2p band gap greatly. Such a modification of the oxygen electronic state is probably related to the electrochemical cell voltage. This lithium intercalation effect still holds even in the alloyed systems. However, the amount of transferred charges from M to O ions changes depending on the alloying element, M. So the alloying addition modifies the oxygen electronic state and influences the lithium intercalation process indirectly. 相似文献
108.
Takashi Matsumura Fumio Iida Takuya Hirose Masahiko Yoshino 《Journal of Materials Processing Technology》2012,212(12):2669-2677
A micro fabrication is presented to manufacture hydrophobic surfaces with micro-scale structures. Hydrophobicity is controlled with the shape and the alignment of micro pillars in the structure. The structures are manufactured in large areas at high production rates in the following processes: (1) the structure is fabricated on a tool by focused ion beam sputtering; (2) the reverse structure is formed on a metal plate by incremental stamping using the structured tool; and (3) the structure is transferred onto plastic plates by molding. A consecutive stamping is also proposed to fabricate several structures on a surface accurately with a structured tool, in which the moving pitch of the structured tool is numerically controlled. The effect of the surface topography on hydrophobicity is discussed with measuring contact angles on the structured surfaces in the water droplet tests. Hydrophobicity on the plastic plate is associated with the solid fraction on the structured surface based on the Cassie–Baxter model. A larger contact angle is observed for a smaller solid fraction of the surface. 相似文献
109.
<正>大船渡市属于日本西北部的岩手县,位于颇具特色的三陆海岸线上。大船渡市民文化会馆暨市立图书馆作为一个文化建筑综合体,包含了一个容纳1100个座位的大剧场、图书室、多功能剧场、画室、茶室以及工作室。工程在进展过程中组织了超过50次的各种区域性研 相似文献
110.
Yasushi Mae Hideyasu Takahashi Kenichi Ohara Tomohito Takubo Tatsuo Arai 《Intelligent Service Robotics》2011,4(1):91-98
The paper presents a robot system design with highly reusable components for a component-based robot system for manipulation
tasks. The robot system is designed based on the analysis of manipulation tasks using a unified modeling language use case
diagram. For a service robot with locomotion and manipulation mechanisms, reusability of robot system components is improved
by adopting the proposed design. Our structure consists of scenario, task, robot information management server, data analyzer,
sensor hardware controller, skill, and motion hardware controller on a component-based robot system. Based on the proposed
robot system, we implemented a component-based robot system and subsequently realized a grasping motion by a service robot. 相似文献