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741.
Qi Zhang Wei Li Da-Chao Lin Yun Duan Hui-Min Liang 《Experimental Thermal and Fluid Science》2011,35(3):503-508
Explosion temperature is one of the main factors in combustible gas explosion accidents. Despite all this, this problem has not yet received considerable attention, especially few fundamental data related to the temperature distribution of gas explosions in closed vessels in literatures. According to characteristics of gas deflagrations, this work developed a gas explosion temperature measurement system whose response time to temperature is approximate 10 μs. By using this system, an experimental study was carried out which is concerned with the deflagration temperature distribution of premixed methane-air mixtures in the 20 L spherical vessel with a diameter of 168 mm. Experimental results show that temperatures on or near the wall are obviously lower than those in the center part of the vessel and there is a conspicuous gradient from the wall to the center part of the vessel. In the inside of the vessel, the deflagration temperature of premixed methane-air mixtures near the ignition spot at the center of the vessel can approximately reach 1200 °C, while near the wall, only 300 °C. This result throws a light on the specific regularity of gas temperature distribution near the boundary. It is possible to provide an important basis for understanding the general characteristics of gas deflagrations in closed vessels as well as choosing good measurement designs. Otherwise, if the ignition is located in the geometrical center of the spherical vessel, velocity of the flame increases with the distance away from the center inside the vessel, and when the flame arrives at the inner wall, this velocity descend sharply. 相似文献
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弹粘塑性双球壳塌缩热点反应模型 总被引:2,自引:0,他引:2
基于Kim的弹粘塑性单球壳塌缩模型,考虑PBX炸药中的粘结剂效应,假设炸药和粘结剂均为弹粘塑性材料,建立了弹粘塑性双球壳塌缩热点反应模型,给出了炸药球壳在冲击压力作用下的速度、应变、温度和化学反应速率的时空分布,以及新的热点反应速率理论表达式。把新的热点反应项与Kim的低压下慢反应项和张震宇提出的高压反应速率方程相结合,得到了新的冲击起爆三项式细观反应速率模型。把该模型加入DYNA2D中,模拟了PBX-9501炸药的一维冲击起爆过程,结果表明:该模型除了可以解释炸药颗粒度和孔隙度的影响外,还可以较好地描述粘结剂强度和含量对PBX炸药冲击起爆感度的影响。 相似文献
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Effects of binders and graphite on the sensitivity of ε-HNIW 总被引:1,自引:0,他引:1
Lan Yu Xiabing Jiang Xueyong Guo Hui Ren Qingjie Jiao 《Journal of Thermal Analysis and Calorimetry》2013,112(3):1343-1349
In order to optimize formulations of PBX based on Hexanitrohexaazaisowurtzitane (HNIW) and meet the application in mixed explosive, the mold powder of HNIW coated by varied binders was obtained by aqueous suspension technology. Several particle sizes of graphite were added as additive with a 0.5 % mass ratio. The experiment results showed that fluorine resin (FPM) was better than polyurethane and cis-butadiene rubber when the mass percentage of binders was fixed at 4 %. The characteristic height of HNIW/FPM (96/4) mold powder was at 28 cm (2.5 kg hammer), while that of the neat HNIW was at 15 cm merely, and the friction explosion probability fell from 100 to 70 %. The addition of flake graphite with proper grain size would reduce the mechanical sensitivity of HNIW and improved the fluxion property of HNIW-based mold powders. The thermal stability characteristic of HNIW FPM (96/4) and HNIW/FPM/G (96/4/0.5) were studied by thermogravimetric analysis (TG) at 10 °C min?1, the peak decomposition temperatures were at 251 and 250 °C, which were closed to that of neat HNIW(249 °C) and also identified superior thermal stability of compound. 相似文献
748.
Qi Shuyuan Li Zhimin Zhou Zunning Cui Yan Zhang Guotao Zhang Tonglai Zhang Jianguo Yang Li 《中国化学》2011,29(1):59-64
A novel energetic coordination compound [Co(DAT)6](ClO4)2 has been synthesized by using 1,5‐diaminotetrazole (DAT) as a ligand and its structure has been characterized using X‐ray single crystal diffraction, elemental analysis and FT‐IR spectroscopy. The central cobalt(II) cation is coordinated by six N atoms from six DAT molecules to form a six‐coordinated and distorted octahedral structure. Di‐dimension layer structure was formed by the extensive intermolecular hydrogen bonds between DAT ligands and ClO?4 anions along a‐axis and b‐axis. Thermal decomposition mechanism of [Co(DAT)6](ClO4)2 was investigated based on differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transform infrared (FT‐IR) spectra. The kinetic parameters of the first exothermic process were studied by applying the Kissinger's and Ozawa‐Doyle's methods. Additionally, the sensitivities of this complex were tested. The results of all the studies show that [Co(DAT)6](ClO4)2 has an extreme potential application as an energetic material. 相似文献
749.
Density functional theory (DFT) with local density approximation (LDA) is employed to study the structural and electronic properties of the high explosive octahydro- 1,3,5, 7-tetranitro-1,3, 5, 7-tetrazocine (HMX) under high pressure compression up to 40 GPa. Pressure dependences of the cell volume, lattice constants, and molecular geometry of solid β-HMX are presented and discussed. It is found that N-N and N-C bonds are subject to significant change. This may implies that these bonds may be related to the sensitivity. The band gap is calculated and plotted as a function of pressure. Compared the experimental results with other theoretical works we find that LDA gives good results. 相似文献
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