全文获取类型
收费全文 | 1422篇 |
免费 | 63篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 77篇 |
综合类 | 3篇 |
化学工业 | 429篇 |
金属工艺 | 54篇 |
机械仪表 | 24篇 |
建筑科学 | 24篇 |
矿业工程 | 1篇 |
能源动力 | 82篇 |
轻工业 | 105篇 |
水利工程 | 4篇 |
石油天然气 | 3篇 |
无线电 | 87篇 |
一般工业技术 | 345篇 |
冶金工业 | 61篇 |
原子能技术 | 45篇 |
自动化技术 | 144篇 |
出版年
2023年 | 8篇 |
2022年 | 19篇 |
2021年 | 36篇 |
2020年 | 16篇 |
2019年 | 36篇 |
2018年 | 39篇 |
2017年 | 33篇 |
2016年 | 49篇 |
2015年 | 38篇 |
2014年 | 39篇 |
2013年 | 76篇 |
2012年 | 83篇 |
2011年 | 108篇 |
2010年 | 67篇 |
2009年 | 87篇 |
2008年 | 81篇 |
2007年 | 71篇 |
2006年 | 45篇 |
2005年 | 46篇 |
2004年 | 57篇 |
2003年 | 44篇 |
2002年 | 33篇 |
2001年 | 33篇 |
2000年 | 18篇 |
1999年 | 26篇 |
1998年 | 31篇 |
1997年 | 33篇 |
1996年 | 24篇 |
1995年 | 13篇 |
1994年 | 16篇 |
1993年 | 20篇 |
1992年 | 18篇 |
1991年 | 27篇 |
1990年 | 12篇 |
1989年 | 15篇 |
1988年 | 6篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1973年 | 2篇 |
1968年 | 2篇 |
排序方式: 共有1488条查询结果,搜索用时 0 毫秒
81.
Takayuki Yamada 《Artificial Life and Robotics》2009,14(3):384-387
Although many neural network controllers have been proposed, we still have to tune several parameters of neural networks in
order to obtain a better learning performance in practical applications. Our tracking method provides a new aspect of this
tuning of neural network parameters. It has been applied to adaptive and learning-type neural network direct controllers,
and an adaptive-type neural network feed-forward feed-back controller. This work applied it to a learning-type neural network
feed-forward feed-back controller. Simulation results confirmed its usefulness, and we discuss a transformation of the track
on a 2D plane to one-dimensional values. 相似文献
82.
Phasemorphology and mechanical properties of blends of high‐impact polystyrene (HIPS) and polycarbonate (PC) blends compatibilized with a polystyrene (PS) and polyarylate (PAr) (PS–PAr) block copolymer were investigated. Over a broad range of composition from 50/50 through 30/70, HIPS/PC blends formed cocontinuous structures induced by the flow during the extrusion or injection‐molding processes. These cocontinuous phases had heterogeneity between the parallel and perpendicular directions to the flow. The micromorphology in the parallel direction to the flow consisted of stringlike phases, which were highly elongated along the flow. Their longitudinal size was long enough to be longer than 180 μm, while their lateral size was shorter than 5 μm, whereas that in the perpendicular direction to the flow showed a cocontinuous phase with regular spacing due to interconnection or blanching among the stringlike phases. The PS–PAr block copolymer was found to successfully compatibilize the HIPS/PC blends. The lateral size of the stringlike phases could be controlled both by the amount of the PS–PAr block copolymer added and by the shear rate during the extrusion or injection‐molding process without changing their longitudinal size. The HIPS/PC blend compatibilized with 3 wt % of the PS–PAr block copolymer under an average shear rate of 675 s?1 showed a stringlike phase whose lateral size was reduced almost equal to the rubber particle size in HIPS. The tensile modulus and yield stress of the HIPS/PC blends could be explained by the addition rule of each component, while the elongation at break was almost equal to that of PC. These mechanical properties of the HIPS/PC blends can be explained by a parallel connection model independent of the HIPS and PC phases. On the other hand, the toughness factor of the HIPS/PC blends strongly depended on the lateral size of the stringlike phases and the rubber particle size in the HIPS. It was found that the size of the string phases and the rubber particle should be smaller than 1.0 μm to attain a reasonable energy absorbency by blending HIPS and PC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2347–2360, 2001 相似文献
83.
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
84.
Yasuyuki Kaneno Tetsuo Yamaguchi Takayuki Takasugi 《Journal of Materials Science》2006,41(20):6871-6880
The texture evolution during the hot-rolling and the recrystallization of B2-type Fe–48Al, Ni–50Al and Co–50Ti (expressed
by at.%) intermetallic compounds were investigated. By hot-rolling at 973 K, Fe–48Al showed a microstructure with coarse grains
elongated along rolling direction, while Ni–50Al and Co–50Ti showed a deformed microstructure featured by the heavily distorted
(elongated) grains and/or the deformation bands. The hot-rolling texture of Fe–48Al was composed of {111}<uvw>, while those
of Ni–50Al and Co–50Ti were composed of {111}<110> and {111}<112>, respectively. After annealing, the recrystallized grains
were preferentially nucleated at the grain boundaries for Fe–48Al, and in the heavily distorted regions or the deformation
bands for Ni–50Al and Co–50Ti. The orientations of the recrystallized grains were similar with those of the deformed matrix,
especially for Ni–50Al and Co–50Ti. The recrystallization textures were generally more dispersive than the hot-rolling texture.
Based on these results, the texture evolution during the hot rolling and the recrystallization of the B2-type intermetallic
compounds were discussed. 相似文献
85.
Development of efficient ultraviolet (UV) rare-gas halide excimer lasers has added new possibilities for laser radar (lidar) technique for monitoring atmospheric constituents. An experimental result of the observation of the stratospheric ozone layer by a XeCl laser (308 nm) based on the differential-absorption-lidar (DIAL) technique is described. The obtained ozone profile in an altitude range of 15- 25 km are in good agreement with those measured by radiosonde. The measurement error is analyzed for one-wavelength lidar. The accuracy is estimated to be 10-30 percent within an altitude range of 10-30 km and at a range resolution of 1 km or less. The accuracy and the resolution are higher than the Umkehr method. Recent progress of rare-gas halide lasers and their frequency conversion techniques as a transmitter for lidar are reviewed. Many powerful and reliable new sources are available in almost every wavelength over the near UV region. New applications of these UV sources to the lidar system are also briefly discussed, especially from the scientific field on the middle atmosphere. 相似文献
86.
Summary To clarify the mechanism of living radical polymerization of methyl methacrylate (MMA) with tetraphenylsuccinodinitrile (TPSN) as a thermal iniferter, a model compound for the end group of the poly(MMA) produced, methyl 2,2-dimethyl-3,3-diphenyl-3-cyanopropionate (2), was synthesized and found to initiate a living radical polymerization of MMA, indicating that the hexa-substituted C-C bond in 2 dissociated into radicals. The poly(MMA) thus obtained further initiated the radical polymerization of styrene (St) to give a block copolymer. 相似文献
87.
We describe an interferometer system that uses two separate wavelengths to measure step height. The overlapping interference images detected by a CCD camera are easily separated by an ordinary integrating-bucket method and time-sharing sinusoidal phase modulation, in which two laser diodes are alternately modulated with a sinusoidal signal. A phase map is obtained only for the laser diode into which the modulation signal is injected. In this instance, a 1-microm step height was accurately detected. 相似文献
88.
Fat-Halla Nabil Takasugi Takayuki Izumi Osamu 《Metallurgical and Materials Transactions A》1979,10(9):1341-1349
The deformation up to fracture at 150 K was undertaken on α-β brass two-phase bicrystals. The variation of the slip systems
during the proceeding deformation was studied and explained on the basis of incompatible stresses. The normal stress-strain
curves were analyzed for various types of bicrystals and the bending that appeared in the specimens when unloaded was explained
with respect to the occurrence of the Bauschinger effect in the α phase. Fracture modes other than those observed at room
temperature were present. The results, and other minor problems, were discussed. 相似文献
89.
Summary The bulk polymerization of methyl methacrylate (MMA) with 1,2-disubstituted tetraphenylethanes, tetraphenylsuccinodinitrile (TPSN), tetra(p-methoxyphenyl)succinodinitrile (TMPSN), and pentaphenylethane (PPE), was investigated. These compounds were found to serve as thermal iniferters to induce living radical polymerization via a mechanism close to the model proposed previously (see Eq. 2). However, the living nature was not so high, because undesirable side reactions occurred. The oligomer with molecular weight of 2500 was isolated from the reaction mixture of MMA with TPSN, which was found to cause further polymerization of MMA. From the polymerization of styrene (St) with the polymers obtained by these iniferters, the block copolymers were produced. 相似文献
90.
High-Temperature Active Oxidation of Chemically Vapor-Deposited Silicon Carbide in CO─CO2 Atmosphere
Takayuki Narushima Takashi Goto Yoshio Yokoyama Yasutaka Iguchi Toshio Hirai 《Journal of the American Ceramic Society》1993,76(10):2521-2524
Active oxidation behavior of CVD-SiC in CO─CO2 atmospheres was investigated using a thermogravimetric technique in the temperature range between 1823 and 1923 K. The gas pressure ratio, P CO2 / P CO , was controlled between 10−4 and 10−1 at 0.1 MPa. Active oxidation rates (mass loss rates) showed maxima at a certain value of P CO2 / P CO , ( P CO2 / P CO )* , In a P CO2 / P CO region lower than the ( P CO2 / P CO )* a carbon layer was formed on the SiC surface. In a P CO2 / P CO region higher than the ( P CO2 / P CO )* , silica particles or a porous silica layer was observed on the SiC surface. 相似文献