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81.
密码芯片运行时的光辐射可泄露其操作和数据的重要特征信息. 基于单光子探测技术, 设计并构建了针对CMOS半导体集成电路芯片光辐射信号的采集、传输、处理和分析的光电实验系统. 以AT89C52单片机作为实验对象, 采用时间相关单光子计数技术, 对不同工作电压下密码芯片的光辐射强度进行了对比, 分析了芯片指令级光辐射信息的操作依赖性和数据依赖性. 此外, 使用示波器对时间相关单光子计数技术在芯片光辐射分析上的可行性进行了验证. 实验结果表明, 采用时间相关单光子计数技术对密码芯片进行光辐射分析, 是一种直接有效的中低等代价光旁路分析攻击手段, 对密码芯片的安全构成了严重的现实威胁. 相似文献
82.
Asymmetric vortices flow over slender body and its active control at high angle of attack 总被引:5,自引:0,他引:5
The studies of asymmetric vortices flow over slender body and its active control at high angles of attack have significant
importance for both academic field and engineering area. This paper attempts to provide an update state of art to the investigations
on the fields of forebody asymmetric vortices. This review emphasizes the correlation between micro-perturbation on the model
nose and its response and evolution behaviors of the asymmetric vortices. The critical issues are discussed, which include
the formation and evolution mechanism of asymmetric multi-vortices; main behaviors of asymmetric vortices flow including its
deterministic feature and vortices flow structure; the evolution and development of asymmetric vortices under the perturbation
on the model nose; forebody vortex active control especially discussed micro-perturbation active control concept and technique
in more detail. However present understanding in this area is still very limited and this paper tries to identify the key
unknown problems in the concluding remarks.
The project supported by the National Natural Science Foundation of China (10172017), Aeronautical Science Foundation of China
(02A51048) and Foundation of National Key Laboratory of Aerodynamic Design and Research (51462020504HK0101) 相似文献
83.
Chen Wang Yao Fu Prof. Qing‐Xiang Guo Prof. Lei Liu Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(8):2586-2598
Quantitative nucleophilicity scales are fundamental to organic chemistry and are usually constructed on the basis of Mayr’s equation [log k=s(N+E)] by using benzhydrylium ions as reference electrophiles. Here an ab initio protocol was developed for the first time to predict the nucleophilicity parameters N of various π nucleophiles in CH2Cl2 through transition‐state calculations. The optimized theoretical model (BH&HLYP/6‐311++G(3df,2p)//B3LYP/6‐311+G(d,p)/PCM/UAHF) could predict the N values of structurally unrelated π nucleophiles within a precision of ca. 1.14 units and therefore may find applications for the prediction of nucleophilicity of compounds that are not readily amenable to experimental characterization. The success in predicting N parameters from first principles also allowed us to analyze in depth the electrostatic, steric, and solvation energies involved in electrophile–nucleophile reactions. We found that solvation does not play an important role in the validity of Mayr’s equation. On the other hand, the correlations of the E, N, and log k values with the energies of the frontier molecular orbitals indicated that electrostatic/charge‐transfer interactions play vital roles in Mayr’s equation. Surprising correlations observed between the electrophile–nucleophile C? C distances in the transition state, the activation energy barriers, and the E and N parameters indicate the importance of steric interactions in Mayr’s equation. A method is then proposed to separate the attraction and repulsion energies in the nucleophile–electrophile interaction. It was found that the attraction energy correlated with N+E, whereas the repulsion energy correlated to the s parameter. 相似文献
84.
Faisal A.A. El-Orany 《Physics letters. A》2010,374(8):1097-1100
In [J.S. Shaari, M. Lucamarini, M.R.B. Wahiddin, Phys. Lett. A 358 (2006) 85] the deterministic six states protocol (6DP) for quantum communication has been developed. This protocol is based on three mutually unbiased bases and four encoding operators. Information is transmitted between the users via two qubits from different bases. Three attacks have been studied; namely intercept-resend attack (IRA), double-CNOT attack (2CNOTA) and quantum man-in-the-middle attack. In this Letter, we show that the IRA and 2CNOTA are not properly addressed. For instance, we show that the probability of detecting Eve in the control mode of the IRA is 70% instead of 50% in the previous study. Moreover, in the 2CNOTA, Eve can only obtain 50% of the data not all of it as argued earlier. 相似文献
85.
Simon G. Bott Sang-Woo Lee Kaiyuan Yang Michael G. Richmond 《Journal of chemical crystallography》2005,35(3):203-209
The reducing agent [Et3BH][Li] reacts with diag-CpRe(CO)2Br2 in THF at –78C by polyene ring attack to give the anionic rhenium(I) compound [(4-C5H6)Re(CO)2Br2]–. Monitoring the reaction by low-temperature IR spectroscopy has revealed that the reaction between diag-CpRe(CO)2Br2 and hydride is instantaneous and that the known compounds CpRe(CO)2Br– and CpRe(CO)2Br(H) are not formed as the principal reduction products. The reduced compound [(4-C5H6)Re(CO)2Br2]– is extremely temperature sensitive and decomposes upon warming to afford low yields of CpRe(CO)3. We have explored the reactivity of the hydride reduction product with added CO and have isolated and structurally characterized the anionic tetracarbonyl compound trans(Br)-[Re(CO)4Br2]– as the tetraphenylphosphonium salt. trans(Br)-[Re(CO)4Br2][PPh4] crystallizes in the monoclinic space group C2/c, a = 16.908(2) Å, b = 7.1579(7) Å, c = 23.543(2) Å, = 96.144(9), V = 2832.9(5) Å3, Z = 4, Dcacl = 1.870 g/cm3; R = 0.0419, Rw = 0.0450 for 1629 observed reflections with I > 3(I). The reaction between the product of hydride reduction and dppe is shown by IR and 31P NMR spectroscopies to produce mer-cis-BrRe(CO)2(2-dppe)(1-dppe). 相似文献
86.
87.
Security of quantum key distribution using two-mode squeezed states against optimal beam splitter attack 下载免费PDF全文
For the beam splitter attack strategy against quantum key distribution using two-mode squeezed states, the analytical expression of the optimal beam splitter parameter is provided in this paper by applying the Shannon information theory. The theoretical secret information rate after error correction and privacy amplification is given in terms of the squeezed parameter and channel parameters. The results show that the two-mode squeezed state quantum key distribution is secure against an optimal beam splitter attack. 相似文献
88.
The possible effects of radiation exposure to DNA are studied by investigations for the thymine residue. Detailed analysis of the various addition and other products is undertaken theoretically, using the semiempirical AM1 procedure. The results agree with the experimental finding that the loss of hydrogen on radiation exposure occurs from the C5-methyl group and hydroxyl radical addition occurs at C6, yielding the ‘5-yl’ radical. This radical is nonplanar, the axial conformer being slightly preferred over the equatorial one. In contrast, the other possible radical, the ‘6-yl’ radical, is almost planar. These results are important in understanding the conformational changes in DNA as a consequence of radiation exposure. 相似文献
89.
YANG Qiu-Ying ZHANG Ying-Yue ZHANG Gui-Qing CHEN Tian-Lun 《理论物理通讯》2008,49(4):965-970
In this paper, we investigate the effect due to the change of topology structure of network on the nonlinear dynamical behavior, by virtue of the OFC neuron evolution model with attack and repair strategy based on the small world. In particular, roles of various parameters relating to the dynamical behavior are carefully studied and analyzed. In addition, the avalanche and EEC-like wave activities with attack and repair strategy are also explored in detail in this work. 相似文献
90.
先计算出高超音速零攻角尖锥边界层的定常层流流场.然后在计算域的入口引入两组有限幅值的T-S波扰动,对空间模式的转捩过程进行了直接数值模拟.分析了转捩过程的机理,发现平均流剖面稳定性的变化是其关键.并进一步讨论了不同模态初始扰动在高超音速尖锥边界层中的演化规律. 相似文献