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991.
Takashi Ogi Ratna Balgis Kikuo Okuyama Naoko Tajima Heru Setyawan 《American Institute of Chemical Engineers》2013,59(8):2753-2760
Platinum‐deposited titanium nitride (Pt/TiN) nanoparticle aggregates with high porosities were successfully prepared via a self‐assembly‐assisted spray pyrolysis method. The addition of formic acid (HCOOH) had a significant influence on the process, promoting the simultaneous formation of metallic Pt and reduction on the surface of the TiN support material. Complete reduction of the Pt/TiN nanoparticle aggregates improved the catalytic activity. The electrochemical surface area (ECSA) of Pt/TiN with HCOOH (Pt/TiNw/HCOOH) was 87.15 m2/g‐Pt, which was higher than that of Pt/TiN without HCOOH (Pt/TiNw/o‐HCOOH). The catalytic durability of Pt/TiNw/HCOOH was twice that of Pt/TiNw/o‐HCOOH. An effective strategy for obtaining carbon‐free catalysts with high activities and durabilities was identified. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2753–2760, 2013 相似文献
992.
Yasutaka Serizawa Yutaro Sekimoto Mamoru Kamikura Wenlei Shan Tetsuya Ito Tomonori Tamura Takashi Noguchi 《Journal of Infrared, Millimeter and Terahertz Waves》2012,33(10):999-1017
A submillimeter (385–500 GHz) low-noise sideband-separating balanced SIS (Superconductor Insulator Superconductor) mixer (Balanced 2SB mixer) with high IRR (Image Rejection Ratio) has been successfully developed, whose SSB (Single SideBand) noise temperature is ~ 200 K (10hf/k) with an image rejection ratio of ≥?~10 dB. Balanced mixers have become a promising technology which would break through the limitation especially in terahertz receivers and heterodyne arrays. However, though there are examples in microwave with relatively worse noise performance, submillimeter and terahertz balanced mixers have rarely been developed in spite of their astronomical importance. The developed balanced 2SB mixer is not only the first one demonstrated at submillimeter frequency range, but also has very low noise, high IRR, wide detectable frequencies (385–500 GHz), and a flat IF output spectrum. The balanced 2SB mixer is composed of three RF hybrids, four DSB (Double SideBand) mixers, two 180° IF hybrids, and an IF quadrature hybrid. Several important performance indicators such as noise temperature, IRR, required LO (Local Oscillator) power, and IF spectra were measured. The measured LO power required for the balanced 2SB mixer was typically ~ 14 dB less than that of the single-ended mixers. 相似文献
993.
This study analyzes the role of energy intensity improvement in the short term (to the year 2020) and midterm (to the year
2050) in the context of long-term greenhouse gases (GHG) stabilization scenarios. The data come from the latest Emissions
Scenarios Database and were reviewed in the Fourth Assessment Report (AR4) by the Intergovernmental Panel on Climate Change.
In this study, quantitative decomposition analyses using the extended Kaya identity are applied to the stabilization scenarios
in Categories I to IV of Table SPM.5 in the AR4. Furthermore, quantitative decomposition analyses of Category IV scenarios
are conducted for major GHG-emitting countries, such as the USA, Western Europe, China, and India, by utilizing the large
number of reports in the database. This study provides in-depth analyses of the relationship between energy intensity improvement
and other major indicators. One finding is that energy intensity improvement plays an important role in the short term, and
the rate of energy intensity improvement is assumed to be around 2% per year as a median value across Categories I–III in
the midterm on the global scale. However, achieving stringent stabilization levels requires various other measures regarding
the use of less-carbon intensive fossil fuels, the shift to non-fossil fuel energies, and advanced technologies such as carbon
capture and storage.
相似文献
Tatsuya HanaokaEmail: |
994.
Takashi Sasaoka Hideki Shimada Takayuki Sasaki Masatomo Ichinose Kikuo Matsui 《煤炭学报(英文版)》2008,14(3):365-368
The size distribution of a muck pile depends not on only the blasting standard but also on the mechanical properties, joint
system, and crack density of the rock mass. As, the cracks in the rock masses are especially heavily developed at the limestone
quarries in Japan, they, along with the joints, have a large impact on the effects of blasting, such as the size of the muck
pile. Therefore, if the joint system and/or crack density in a rock mass can be determined and quantitatively evaluated, the
blasting operation can be conducted more effectively, efficiently and safely. However, guidelines for designing appropriate
blasting standards based on the rock mass conditions have not yet been scientifically developed. Therefore, blasting tests
were conducted on different mines and faces, under different geological conditions and blasting standards, in order to determine
the impacts of each factor on the effects of blasting. Summarized the results of a series of blasting tests and described
the impacts of geological conditions on the size of the muck pile produced by blast.
Bhandari S. Engineering rock blasting operations, 1997. 相似文献
995.
Toshiaki Kitagawa Takashi NakaharaKosuke Maruyama Kunihiro KadoAkihiro Hayakawa Shoichi Kobayashi 《International Journal of Hydrogen Energy》2008
Lewis number represents the thermo-diffusive effects on laminar flames. That of hydrogen–air mixture varies extensively with the equivalence ratio due to the high molecular diffusivity of hydrogen. In this study, the influences of pressure and thermo-diffusive effects on spherically propagating premixed hydrogen–air turbulent flames were studied using a constant volume fan-stirred combustion vessel. It was noted that the ratio of the turbulent to unstretched laminar burning velocity increased with decreasing equivalence ratio and increasing mixture pressure. Turbulent burning velocity was dominated by three factors: (1) purely hydrodynamic factor, turbulence Reynolds number, (2) relative turbulence intensity to reaction speed, the ratio of turbulence intensity to unstretched laminar burning velocity, and (3) sensitivity of the flame to the stretch due to the thermo-diffusive effects, Lewis and Markstein numbers. A turbulent burning velocity correlation in terms of Reynolds and Lewis numbers is presented. 相似文献
996.
Kohei Miyazaki Naotsugu Sugimura Koji Matsuoka Yasutoshi Iriyama Takeshi Abe Masao Matsuoka Zempachi Ogumi 《Journal of power sources》2008
Carbon-supported La1−xSrxMnO3 (LSM/C) was prepared by reversible homogeneous precipitation method, and its catalytic activities for oxygen reduction under the existence of ethylene glycol (EG) were investigated by using rotating disk electrode. LSM/C exhibited the high activity for oxygen reduction irrespective with the presence of EG, indicating that EG is not oxidized by LSM/C at the cathode side in the present system. Consequently, LSM/C can serve as a cathode catalyst in alkaline direct alcohol fuel cells with no crossover problem. Performance test for fuel cells operation also supported these results and showed cathodic polarization curves were not affected by the concentration of EG supplied to anode even at 5 mol dm−3. 相似文献
997.
Takeshi Kobayashi Yuki Imade Daisuke Shishihara Kenji Homma Miki Nagao Ryota Watanabe Toshiyuki Yokoi Atsuo Yamada Ryoji Kanno Takashi Tatsumi 《Journal of power sources》2008
A high-capacity type of all solid-state battery was developed using sulfur electrode and the thio-LISICON electrolyte. New nano-composite of sulfur and acetylene black (AB) with an average particle size of 1–10 nm was fabricated by gas-phase mixing and showed a reversible capacity of 900 mAh g−1 at a current density of 0.013 mA cm−2. 相似文献
998.
999.
Naoki Miura Yukio Takahashi Yasunari Nakayama Kenichi Fujishita Takashi Shimakawa 《Nuclear Engineering and Design》2008,238(2):435-442
In the design assessment of fast reactor plant components, prevention of crack initiation from defect-free structures is a main concern. However, existence of initial defects such as weld defects cannot be entirely excluded and this potential cracks are to be evaluated to determine if initiated cracks do not lead to component failure instantly. Therefore, evaluation of structural integrity in the presence of crack-like defects is also important to complement the formal design assessment. The authors have been developing a guideline for assessing long-term structural integrity of fast reactor components using detailed inelastic analysis and nonlinear fracture mechanics. This guideline consists of two parts, evaluation of defect-free structures and flaw evaluation. In the latter, creep-fatigue is considered to be one of the most essential driving force for crack propagation at high operating temperature exceeding 500 °C. The uses of J-integral-type parameters (fatigue J-integral range and creep J-integral) are recommended to describe creep-fatigue crack propagation behavior in the guideline. This paper gives an outline of the simplified evaluation method for creep-fatigue crack propagation. 相似文献
1000.
Keiichiro Tohgo Hiromitsu Suzuki Yoshinobu Shimamura Guen Nakayama Takashi Hirano 《Corrosion Science》2009,51(9):2208-2217
Stress corrosion cracking (SCC) on a smooth surface of structural metal materials occurs by initiation and coalescence of micro cracks, subcritical crack propagation and multiple large crack formation or final failure under combination of material, stress and corrosive environment. In this paper, a Monte Carlo simulation of the SCC process is proposed based on stochastic properties for micro crack initiation and concepts in fracture mechanics for crack coalescence and propagation. The procedure is as follows: The possible number of grain-sized micro cracks which can be initiated is set for a given space and initiation times for all cracks are assigned by random numbers based on exponential distribution. Sites and sizes of cracks are assigned by uniform random numbers and normal random numbers, respectively. Coalescence and propagation of cracks are determined based on fracture mechanics. The emphasis in the model is put on the influence of semi-elliptical surface cracks. Numerical simulations are carried out based on the results of creviced-bent-beam tests for sensitized stainless steel type 304 under high-temperature and high-purity water containing dissolved oxygen and the influence of micro crack initiation rate and coalescence condition on the simulation results is discussed. 相似文献