全文获取类型
收费全文 | 2979篇 |
免费 | 74篇 |
国内免费 | 19篇 |
专业分类
电工技术 | 183篇 |
综合类 | 5篇 |
化学工业 | 974篇 |
金属工艺 | 96篇 |
机械仪表 | 104篇 |
建筑科学 | 93篇 |
能源动力 | 140篇 |
轻工业 | 192篇 |
水利工程 | 6篇 |
石油天然气 | 3篇 |
无线电 | 148篇 |
一般工业技术 | 694篇 |
冶金工业 | 86篇 |
原子能技术 | 116篇 |
自动化技术 | 232篇 |
出版年
2023年 | 15篇 |
2022年 | 14篇 |
2021年 | 50篇 |
2020年 | 21篇 |
2019年 | 32篇 |
2018年 | 51篇 |
2017年 | 45篇 |
2016年 | 58篇 |
2015年 | 48篇 |
2014年 | 69篇 |
2013年 | 161篇 |
2012年 | 104篇 |
2011年 | 197篇 |
2010年 | 138篇 |
2009年 | 145篇 |
2008年 | 169篇 |
2007年 | 112篇 |
2006年 | 134篇 |
2005年 | 116篇 |
2004年 | 84篇 |
2003年 | 116篇 |
2002年 | 82篇 |
2001年 | 55篇 |
2000年 | 66篇 |
1999年 | 54篇 |
1998年 | 72篇 |
1997年 | 78篇 |
1996年 | 64篇 |
1995年 | 42篇 |
1994年 | 33篇 |
1993年 | 45篇 |
1992年 | 30篇 |
1991年 | 27篇 |
1990年 | 32篇 |
1989年 | 45篇 |
1988年 | 31篇 |
1987年 | 34篇 |
1986年 | 53篇 |
1985年 | 44篇 |
1984年 | 56篇 |
1983年 | 49篇 |
1982年 | 32篇 |
1981年 | 24篇 |
1980年 | 19篇 |
1979年 | 27篇 |
1978年 | 19篇 |
1977年 | 18篇 |
1976年 | 10篇 |
1974年 | 14篇 |
1973年 | 10篇 |
排序方式: 共有3072条查询结果,搜索用时 15 毫秒
101.
Akane Yamamichi Fumiharu Ohka Hiromichi Suzuki Akira Kato Kazuya Motomura 《Science and Technology of Advanced Materials》2016,17(1):618-625
World Health Organization grade II and III gliomas most frequently occur in the central nervous system (CNS) in adults. Gliomas are not circumscribed; tumor edges are irregular and consist of tumor cells, normal brain tissue, and hyperplastic reactive glial cells. Therefore, the tumors are not fully resectable, resulting in recurrence, malignant progression, and eventual death. Approximately 69–80% of grade II and III gliomas harbor mutations in the isocitrate dehydrogenase 1 gene (IDH1), of which 83–90% are found to be the IDH1-R132H mutation. Detection of the IDH1-R132H mutation should help in the differential diagnosis of grade II and III gliomas from other types of CNS tumors and help determine the boundary between the tumor and normal brain tissue. In this study, we established a highly sensitive antibody-based device, referred to as the immuno-wall, to detect the IDH1-R132H mutation in gliomas. The immuno-wall causes an immunoreaction in microchannels fabricated using a photo-polymerizing polymer. This microdevice enables the analysis of the IDH1 status with a small sample within 15 min with substantially high sensitivity. Our results suggested that 10% content of the IDH1-R132H mutation in a sample of 0.33 μl volume, with 500 ng protein, or from 500 cells is theoretically sufficient for the analysis. The immuno-wall device will enable the rapid and highly sensitive detection of the IDH1-R132H mutation in routine clinical practice. 相似文献
102.
Takayuki Sasaki Takayuki Koukami Taishi Kobayashi Akira Kirishima Hiroaki Murakami Yuki Amano 《Journal of Nuclear Science and Technology》2017,54(3):373-381
At two underground research laboratories situated at Horonobe and Mizunami, Japan, trace amounts of natural thorium and uranium dissolved in deep groundwater were investigated with the help of chemical pre-concentration method. The groundwater was sampled from underground boreholes under the geochemical condition of no atmospheric exposure, and the colloid contribution was checked by in situ two size-fractionated ultrafiltration systems. A rough decrease by half in the concentration after in situ filtration suggested the presence of natural colloids and suspended matter that were carriers of a portion of the elements. The Th and U concentrations in groundwater after 10 kDa filtration was evaluated as dissolved species, and was identified thermodynamically using existing hydrogeological and geochemical data, such as the mineral components in the groundwater at a given pH, ionic strength, concentration of co-existing ions, redox potential, and a hypothetical solubility-limiting solid phase. The crystalline solid phase of tetravalent thorium and uranium dioxides made the solubility very low compared with that of the amorphous phase. 相似文献
103.
Kiyoharu Nakagawa Hirokazu Oda Akira Yamashita Masahiro Okamoto Yoichi Sato Hidenori Gamo Mikka Nishitani-Gamo Kazuyuki Ogawa Toshihiro Ando 《Journal of Materials Science》2009,44(1):221-226
We developed a novel spherical carbon material. The spherical carbon is composed of a high density of carbon nanotubes or
nanofilaments, and includes an oxidized diamond particle as a core. Syntheses of this carbon in high volume with high selectivity
may be possible. It is expected that this carbon will be useful as a catalyst material for fuel cells, electric double-layer
capacitors, etc. 相似文献
104.
In this study, we prepared monodisperse spherical particles of a desired diameter using [(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4 alloy; the particles were prepared by using an atomization process developed by us. The particles have perfect sphericity and narrow size distribution along with a homogeneous composition. The phase transitions of particles from the fully glassy phase to the crystalline phase via mixed phase structures occurred as the particle diameter was increased; the particles produced in the fully glassy phase in an argon atmosphere had a diameter of less than 300 μm. This allowed the estimation of the intrinsic critical cooling rate for the particles with a fully glassy phase, Rc:Rc varied in the range of 700-900 K/s and depended only on the initial temperature of the alloy melt. 相似文献
105.
Hiroki Ishikawa Ryoko Komaki Haruo Naitoh Akira Yamaba Hiroki Katoh 《Electrical Engineering in Japan》2010,173(1):51-59
This paper presents a current control design for switched reluctance motors (SRMs). The electric transfer characteristic of the motors is studied first. Their transfer function is shown to be expressible by a pure resistive component, which is not constant but varies depending on the motor current and speed. The current control design for SRMs follows the classical design technique used for DC machines, where the zeros of the PI controller cancel the poles of Ls+R. Because the transfer function of SRMs does not have any poles, an I controller is suitable for them. The integral gain should be adjusted in order to compensate the nonlinearity, that is, the variation in the equivalent resistor of the SRMs' transfer function. The values of the integral gain are tuned and tabulated for the motor speed and current. Simulation and experiment demonstrate that the current and speed of the SRMs present good responses without dependence on the motor speed and current. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(1): 51–59, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20987 相似文献
106.
Koh Matsumoto Kazutada Ikenaga Jun Yamamoto Kazuki Naito Yoshiki Yano Akinori Ubukata Hiroki Tokunaga Tadanobu Arimura Katsuaki Cho Toshiya Tabuchi Akira Yamaguchi Yasuhiro Harada Yuzaburo Ban Kousuke Uchiyama 《半导体学报》2011,32(1):21-23
Growth rate has a direct impact on the productivity of nitride LED production.Atmospheric pressure growth of GaN with a growth rate as high as 10μm/h and also Al0.1Ga0.9N growth of 1μm/h by using 4 inch by 11 production scale MOVPE are described.XRD of(002) and(102) direction was 200 arcsec and 250 arcsec, respectively.Impact of the growth rate on productivity is discussed. 相似文献
107.
Noboru Nishioka Miyuki Funakoshi Kohji Inamoto Masakuni Uno Akira Ueda 《应用聚合物科学杂志》2010,118(4):2482-2487
Homogeneous grafting of styrene onto cellulose was carried out in a dimethylacetamide/lithium chloride solvent system. The grafted products were added to cellulose/polystyrene (PS) blends as compatibilizers. The thermal decomposition behavior of the blends was investigated by thermogravimetry. The thermal stability of the blends decreased with an increase in grafted product content. The crystallinity of the blends decreased with grafted product content. The microphase‐separated structures of the blends became finer with grafted product content. The glass transition temperatures for cellulose and PS in the blends were lowered with grafted product content. Differences in thermal decomposition behavior of the blends were correlated with compatibility. Thermogravimetry was effective for compatibility estimation in cellulose/PS blends containing grafted products. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
108.
Ryoji Katoh Masakuni OzawaYoshitaka Ino Akira Kagohashi 《Journal of the European Ceramic Society》2011,31(14):2441-2445
The morphology of CuO powders formed by a homogeneous precipitation process from aqueous copper precursor complex was investigated. The effect of 2.45 GHz microwave irradiation appeared in the characteristic morphology of the CuO microcrystal with comparison of an ordinal synthesis process. The crystallographic orientation of CuO microcrystals in the particle was examined by HRTEM. Using microwave irradiation, it was demonstrated that the morphology of the particles was kept through the decomposition of the precursor. Also the rapid transformation of a precursor to CuO in aqueous solution under microwave irradiation condition was discussed. 相似文献
109.
110.
Kei Masaki Yusuke K. Shibama Shinji Sakurai Masahiro Katayama Akira Sakasai 《Fusion Engineering and Design》2011,86(9-11):1872-1876
JT-60 is planned to be upgraded to JT-60SA tokamak machine with fully superconducting coils, which is a project of the JA-EU satellite tokamak program under both Broader Approach program and Japanese domestic program. The JT-60SA vacuum vessel (VV) has a D-shape poloidal cross section and a toroidal configuration with 10° facet segmented in toroidal direction. The material of the VV is 316L stainless steel with low cobalt content of <0.05 wt%. A double wall structure is adopted for the VV to ensure high rigidity and high toroidal one-turn resistance simultaneously.Fundamental welding R&D and a trial manufacturing of the 20° upper half of the VV have been performed to study the manufacturing procedure. After the confirmation of the quality of the mock-up, manufacturing of the actual VV started in November 2009. 相似文献