全文获取类型
收费全文 | 1497篇 |
免费 | 59篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 67篇 |
综合类 | 1篇 |
化学工业 | 294篇 |
金属工艺 | 37篇 |
机械仪表 | 41篇 |
建筑科学 | 29篇 |
能源动力 | 47篇 |
轻工业 | 89篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 179篇 |
一般工业技术 | 237篇 |
冶金工业 | 366篇 |
原子能技术 | 46篇 |
自动化技术 | 117篇 |
出版年
2023年 | 12篇 |
2022年 | 18篇 |
2021年 | 44篇 |
2020年 | 20篇 |
2019年 | 19篇 |
2018年 | 29篇 |
2017年 | 27篇 |
2016年 | 45篇 |
2015年 | 30篇 |
2014年 | 40篇 |
2013年 | 77篇 |
2012年 | 64篇 |
2011年 | 72篇 |
2010年 | 71篇 |
2009年 | 57篇 |
2008年 | 58篇 |
2007年 | 41篇 |
2006年 | 54篇 |
2005年 | 39篇 |
2004年 | 27篇 |
2003年 | 29篇 |
2002年 | 27篇 |
2001年 | 30篇 |
2000年 | 24篇 |
1999年 | 36篇 |
1998年 | 133篇 |
1997年 | 91篇 |
1996年 | 76篇 |
1995年 | 30篇 |
1994年 | 32篇 |
1993年 | 35篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 19篇 |
1988年 | 17篇 |
1987年 | 11篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 10篇 |
1976年 | 7篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1969年 | 3篇 |
排序方式: 共有1558条查询结果,搜索用时 15 毫秒
51.
Out‐of‐Plane Strain Induced in a Moiré Superstructure of Monolayer MoS2 and MoSe2 on Au(111) 下载免费PDF全文
Satoshi Yasuda Ryosuke Takahashi Ryo Osaka Ryota Kumagai Yasumitsu Miyata Susumu Okada Yuhei Hayamizu Kei Murakoshi 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(31)
Making contact of transition metal dichalcogenides (TMDCs) with a metal surface is essential for fabricating and designing electronic devices and catalytic systems. It also generates strain in the TMDCs that plays significant role in both electronic and phonon structures. Therefore, detailed understanding of mechanism of the strain generation is important to fully comprehend the modulation effect for the electronic and phonon properties. Here, MoS2 and MoSe2 monolayers are grown on Au surface by chemical vapor deposition and it is demonstrated that the contact with a crystalline Au(111) surface gives rise to only out‐of‐plane strain in both MoS2 and MoSe2 layers, whereas no strain generation is observed on polycrystalline Au or SiO2/Si surfaces. Scanning tunneling microscopy analysis provides information regarding consequent specific adsorption sites between lower S (Se) atoms in the S? Mo? S (Se? Mo? Se) structure and Au atoms via unique moiré superstructure formation for MoS2 and MoSe2 layers on Au(111). This observation indicates that the specific adsorption sites give rise to out‐of‐plane strain in the TMDC layers. Furthermore, it also leads to effective modulation of the electronic structure of the MoS2 or MoSe2 layer. 相似文献
52.
Katsumasa Tsurushima Masanobu Tsubaki Tomoya Takeda Takuya Matsuda Akihiro Kimura Honoka Takefuji Akane Okada Chiaki Sakamoto Toshihiko Ishizaka Shozo Nishida 《International journal of molecular sciences》2022,23(15)
Triple-negative breast cancer (TNBC) has the poorest prognosis of all breast cancer subtypes. Recently, the activation of NF-κB, which is involved in the growth and survival of malignant tumors, has been demonstrated in TNBC, suggesting that NF-κB may serve as a new therapeutic target. In the present study, we examined whether dimethyl fumarate (DMF), an NF-κB inhibitor, induces apoptosis in TNBC cells and enhances the apoptosis-inducing effect of paclitaxel and adriamycin. Cell survival was analyzed by the trypan blue assay and apoptosis assay. Protein detection was examined by immunoblotting. The activation of NF-κB p65 was correlated with poor prognosis in patients with TNBC. DMF induced apoptosis in MDA-MB-231 and BT-549 cells at concentrations that were non-cytotoxic to the normal mammary cell line MCF-10A. Furthermore, DMF inhibited NF-κB nuclear translocation and Survivin, XIAP, Bcl-xL, and Bcl-2 expression in MDA-MB-231 and BT-549 cells. Moreover, DMF enhanced the apoptosis-inducing effect of paclitaxel and adriamycin in MDA-MB-231 cells. These findings suggest that DMF may be an effective therapeutic agent for the treatment of TNBC, in which NF-κB is constitutively active. DMF may also be useful as an adjuvant therapy to conventional anticancer drugs. 相似文献
53.
Our previous work identified thermal instability of p-type skutterudite as a primary cause of degradation during thermoelectric generator operation at 650°C. Residual Sb in the microstructure was believed to be the cause of diminished thermal stability, especially above the melting point of Sb (631°C). This work investigated addition of Nb to p-type skutterudite to from NbSb2, thus scavenging elemental Sb. The results of this work are reported, along with comprehensive thermoelectric property characterization of the p-type skutterudite?+?NbSb2 composites. 相似文献
54.
Ryota Miyata Toru Aonishi Jun Tsuzurugi Koji Kurata 《Artificial Life and Robotics》2012,17(1):163-167
In this paper, we investigate the effect of synaptogenesis on memories in the brain, using the abstract-associative memory model, Hopfield model with the zero-order synaptic decay. Using the numerical simulation, we demonstrate the possibility that synaptogenesis plays a role in maintaining recent memories embedded in the network while avoiding overloading. For the network consisting of 1000 units, it turned out that the minimum decay rate to avoid overloading is 0.02, and the optimal decay rate to maximize the storage capacity is 0.08. We also show that the average numbers of replacement synapses at each learning step corresponding to these two values are 1187 and 21024, respectively. 相似文献
55.
Yoshimitsu Yamada Takashi Tsuchida Nyan Myint Kyaw Tatsuru Aoyama Moe Myint Su Hlaing Ryota Hashimoto 《Soils and Foundations》2019,59(6):2279-2298
Recently, a great deal of foreign investment has been entered into construction of the social infrastructure of Myanmar. Many construction projects are therefore on-going, and these are especially planned in the Yangon area. While these construction booms are increasing, existing studies on the geotechnical problems in the Yangon area such as problematic soils like soft clays are limited at present. Information on soil properties has also not been shared and has been confined to individual projects. In this paper, the boring and laboratory tests carried out in the Yangon area are selected and focused upon among the tests carried out in Myanmar. Laboratory test results for clay deposits in the Yangon area are analyzed and the differences in soil properties between different sedimentary basins and sub-areas divided by the Tertiary sediment ridge that runs from north to south at the center of Yangon are clarified together with a comparison to the clays found in other countries, which have been previously investigated. 相似文献
56.
We investigated a simple field effect passivation of the silicon surfaces using the high-pressure H2O vapor heating. Heat treatment with 2.1×106 Pa H2O vapor at 260°C for 3 h reduced the surface recombination velocity from 405 cm/s (before the heat treatment) to 38 cm/s for the thermally evaporated SiOx film/Si. Additional deposition of 140 nm-SiOx films (x<2) with a high density of fixed positive charges on the SiO2/Si samples further decreased the surface recombination velocity to 22 cm/s. We also demonstrated the field effect passivation for n-type silicon wafer coated with thermally grown SiO2. Additional deposition of 210 nm SiOx films on both the front and rear surfaces increased the effective lifetime from 1.4 to 4.6 ms. Combination of thermal evaporation of SiOx film and the heat treatment with high-pressure H2O vapor is effective for low-temperature passivation of the silicon surface. 相似文献
57.
Toughening of Silicon Nitride Matrix Composites by the Addition of Both Silicon Carbide Whiskers and Silicon Carbide Particles 总被引:1,自引:0,他引:1
Hironori Kodama Takaaki Suzuki Hiroshi Sakamoto Tadahiko Miyoshi 《Journal of the American Ceramic Society》1990,73(3):678-683
Si3 N4 matrix composites reinforced by SiC whiskers, SiC particles, or both were fabricated using the hot-pressing technique. The mechanical properties of the composites containing various amounts of these SiC reinforcing materials and different sizes of SiC particles were investigated. Fracture toughness of the composites was significantly improved by introducing SiC whiskers and particles together, compared with that obtained by adding SiC whiskers or SiC particles alone. On increasing the size of the added SiC particles, the fracture toughness of the composites reinforced by both whiskers and particles was increased. Their fracture toughness also showed a strong dependence on the amount of SiC particles (average size 40 μm) and was a maximum at the particle content of 10 vol%. The maximum fracture toughness of these composites was 10.5 MPa·m1/2 and the flexural strength was 550 MPa after addition of 20 vol% of SiC whiskers and 10 vol% of SiC particles having an average particle size of 40 μm. These mechanical properties were almost constant from room temperature to temperatures around 1000°C. Fracture surface observations revealed that the reinforcing mechanisms acting in these composites were crack deflection and crack branching by SiC particles and pullout of SiC whiskers. 相似文献
58.
Yusuke Furuta Hiroyuki Nishikawa Takahiro Satoh Yasuyuki Ishii Tomihiro Kamiya Ryota Nakao Satoshi Uchida 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(12-13):2285-2288
Fabrication of high-aspect-ratio microstructures was performed by proton beam writing (PBW) using a microbeam line at Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), JAEA Takasaki, JAPAN. As one of the applications of the high-aspect-ratio structures micro-machined by PBW, we utilized the high-aspect pillars for electric-micro filters of microbes such as Escherichia coli and Yeast based on the dielectrophoretic force. The filter is equipped with high-aspect pillars with a height of ~20 μm and a diameter of ~1 μm on a glass plate. Evaluation of the dielectrophoresis (DEP) device for capturing E. coli and Yeast was made using either observation by optical microscope or photoluminescence (PL) measurements. 相似文献
59.
R.W. Callis J.L. Doane H.J. Grunloh K. Kajiwara A. Kasugai C.P. Moeller Y. Oda R.A. Olstad K. Sakamoto K. Takahashi 《Fusion Engineering and Design》2009,84(2-6):526-529
Initial testing on the Japan Atomic Energy Agency Gyrotron Test Stand of ITER-relevant TL components, has shown reasonable efficiencies, but identified that trapped modes between closely located miter bends, as well as mode conversion at miter bends can lead to excessive heating of the connecting waveguides. General Atomics has designed, built, and will test components to address this issue as well as ITER relevant components that have not been tested at the levels of 1 MW, 170 GHz, for extended pulse lengths. Some of the components that will be tested are ultra low loss miter bends, dc breaks, polarizers, power monitors, bellows, waveguide switches, waveguide cooling clamps, etc. Details of the components and test results will be presented. 相似文献
60.
Gen Ariyoshi Ryota Inatomi Daisuke Ito 《Journal of Nuclear Science and Technology》2018,55(3):239-253
Lead–bismuth two-phase flow in a cylindrical vessel and annulus was experimentally investigated by varying the surface wettability of the vessel wall. The test section used in this study was a cylindrical stainless vessel with/without inner sleeve to change the hydraulic diameter. Volume-averaged void fraction was measured by varying the surface wettability of the test section, which was enhanced by using a soldering flux. Measured void fraction was compared with existing two-phase flow correlations and with one-dimensional theoretical simulations assuming one-dimensional drift-flux model. From experimental results, measured distribution parameters of the lead–bismuth two-phase flow are much larger than that of ordinary two-phase flow regardless of the surface wettability. In the present work, the one-dimensional analysis was carried out for the cylindrical vessel to reproduce the distribution parameter. From the simulation results, predicted value for the cylindrical vessel showed good agreement with experimental results. However, in annulus, the distribution parameters in annulus were underestimated by the present model. It was suggested that, in case of annulus, steeper void fraction profile might be formed near the inner surface for poor wettability condition. 相似文献