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81.
Lei Pang Yingjuan Shao Wenqi Zhong Hao Liu 《Proceedings of the Combustion Institute》2021,38(3):4121-4129
Oxy-coal combustion with pressurized fluidized beds has recently emerged as a promising carbon capture and storage (CCS) technology for coal-fired power plants. Although a large number of energy efficiency analyses have shown that an increase in combustion pressure can further increase the net plant efficiency, there are few experimental studies of pressurized oxy-coal combustion conducted on fluidized bed combustors/boilers with continuous coal feeding. In this study, oxy-coal combustion experiments with lignite and anthracite were conducted with a 30 kWth pressurized fluidized bed combustor within the pressure range of 0.1 MPa to 0.4 MPa. The investigation focused on the elucidation of the impacts of combustion pressure on the combustion performance, pollutant emissions and desulfurization of oxy-coal combustion in fluidized beds. The results showed that an increase in pressure increased the combustion efficiency and combustion rate of coal particles, and the promoting effect of pressure increase was more significant for the high rank coal with smaller particle size and the high O2 concentration atmosphere. For both coals, NOx emissions decreased with pressure but N2O emissions increased with pressure and accounted for a considerable part of the nitrogen oxide pollutants under high pressure oxy-coal combustion conditions. The pressure had insignificant impact on the SO2 emissions of oxy-coal combustion but an increase in pressure enhanced the direct desulfurization of limestone. 相似文献
82.
Rishav Choudhary Julian J. Girard Sean Clees Sarah E. Johnson Jiankun Shao David F. Davidson Ronald K. Hanson Allen A. Aradi 《Proceedings of the Combustion Institute》2021,38(1):957-965
We report the first shock tube measurements of formaldehyde (CH2O) during the first stage ignition of n-heptane, 2-methylhexane and 3,3-dimethylpentane, in highly diluted fuel/oxygen mixtures in the pressure range of 7–10 atm and temperature range of 700–880 K. Combined time histories of all carbonyl (–C = O) species, CO and fuel were also measured simultaneously in an effort to study the impact of fuel structure on the concentration and the rate of evolution of first stage ignition products. Of the three isomers studied in this work, n-heptane was found to be the fastest, while 3,3-dimethylpentane was found to be the slowest. The differences in the time scale of formation, and plateau concentration of the intermediates between the isomers across the entire range of test conditions suggests a strong dependency of the measured time histories to fuel structure. These species therefore act as markers of the Negative Temperature Coefficient (NTC) behavior of fuels and can be used as targets for developing semi-empirical, hybrid chemistry models of complex, multi-component petroleum derived gasoline and jet fuels. The time histories reported in this work should prove very useful in the refinement of detailed kinetic models of n-heptane, and development of rate rules for branched alkane isomers. 相似文献
83.
Lei Peng Da Xu Xiaohong Yang Jiakun Tang Xuli Feng Shao‐Lin Zhang Hailong Yan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(1):222-226
An organocatalytic one‐step desymmetrizing dearomatization reaction of indoles with in situ formed vinylidene ortho‐quinone methides is reported. A set of [6‐6‐5] and/or [5‐6‐5] fused indoline heterocycles were obtained in excellent yields with excellent diastereoselectivities (>20:1 d.r.) and enantioselectivities (up to 99 % ee). Moreover, some of the obtained products were screened against a panel of cancer cell lines, and one was identified to inhibit the proliferation of all the tested cancer cells, but showed marginal effects against non‐cancerous cells. The methodology provides a platform for the synthesis of new leading compounds with antitumor activity. 相似文献
84.
Wu Tong Dr. Qi Shao Pengtang Wang Prof. Xiaoqing Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(29):7218-7224
The design and development of non-noble metal alternatives with superior performance and promising long-term stability that is comparable or even better than those of noble-metal-based catalysts is a significant challenge. Here, we report the thermal-induced phase engineering of non-noble-metal-based nanowires with superior electrochemical activity and stability for the methanol oxidation reaction (MOR) under alkaline conditions. The optimized Cu–Ni nanowires deliver an unprecedented mass activity of 425 mA mg−1, which is 4.3 times higher than that of the untreated one. Detailed catalytic investigations show that the enhanced performance is due to the large active area, the increased number of active sites (NiOOH), and fast methanol electrooxidation kinetics. In addition, the generated hollow feature in the nanowires provides a unique void space to release the volume expansion, where the activity can be maintained for 5 h without a distinct activity decay. The present work emphasizes the importance of precisely phase modulating of nanomaterials for the design of non-noble metal electrocatalysts towards the MOR, which opens up a new pathway for the design of cost-effective electrocatalysts with promising activity and long-term stability. 相似文献
85.
Jiankun Shao Rishav Choudhary David F. Davidson Ronald K. Hanson Samuel Barak Subith Vasu 《Proceedings of the Combustion Institute》2019,37(4):4555-4562
The need for more efficient power cycles has attracted interest in super-critical CO2 (sCO2) cycles. However, the effects of high CO2 dilution on auto-ignition at extremely high pressures has not been studied in depth. As part of the effort to understand oxy-fuel combustion with massive CO2 dilution, we have measured shock tube ignition delay times (IDT) for methane/O2/CO2 mixtures and hydrogen/O2/CO2 mixtures using sidewall pressure and OH* emission near 306?nm. Ignition delay time was measured in two different facilities behind reflected shock waves over a range of temperatures, 1045–1578?K, in different pressures and mixture regimes, i.e., CH4/O2/CO2 mixtures at 27–286 atm and H2/O2/CO2 mixtures at 37–311 atm. The measured data were compared with the predictions of two recent kinetics models. Fair agreement was found between model and experiment over most of the operating conditions studied. For those conditions where kinetic models fail, the current ignition delay time measurements provide useful target data for development and validation of the mechanisms. 相似文献
86.
High-order curvilinear mesh generation technique based on an improved radius basic function approach
A high-order curvilinear hybrid mesh generation technique is developed for high-order numerical method (eg, discontinuous Galerkin method) applications to improve the accuracy for problems with curve boundary. The grid generation technique is based on an improved radius basic function (RBF) approach by which the straight-edge mesh is converted into high-order curve mesh. Firstly, an initial straight-edge mesh is prepared by traditional grid generation software. Then, high-order interpolation points are inserted into the mesh entities such as edges, faces, and cells according to the final demand of mesh order. To preserve the original geometry, the inserted points on solid wall are then projected onto the CAD model using an open source tool “Open Cascade.” Finally, other inserted points in the field near the solid wall are moved to appropriate positions by the improved RBF approach to avoid tangled cells. If we use the original RBF approach, then the inserted points on the edge and face entities normal to the solid boundary in the region of boundary layer will move to improper positions. To overcome this problem, a weighting based on the local grid aspect ratio between normal direction and tangential direction is introduced into the baseline RBF approach. Three typical configurations are tested to validate the mesh generator. Meanwhile, a third-order solution of subsonic flow over an analytical 3D body of revolution in the second International Workshop on High-Order CFD Methods is supplied by a discontinuous Galerkin solver. These numerical tests demonstrate the potential capability of present technique for high-order simulations of complex geometries. 相似文献
87.
Li Xuetian Shao Zhongbao Liu Kuiren Zhao Qing Liu Guangfu Xu Binshi 《Journal of Solid State Electrochemistry》2019,23(2):465-473
Journal of Solid State Electrochemistry - Li1-xNbxFePO4/C has been prepared by wet mechanical stirring–assisted high-temperature ball milling route. Wet mechanical stirring was considered to... 相似文献
88.
Hui Li Zejun Jiang Xiaolin Cao Hang Su Hua Shao Fen Jin Lufei Zheng A. M. Abd El-Aty Jing Wang 《Chromatographia》2018,81(2):359-364
89.
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