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41.
提出了基于提升方案的自适应算子自定义小波有限元法,构造了一种新的算子自定义小波薄板单元。建立二维Hermite型有限元多分辨空间和两尺度关系,并由广义变分原理推导薄板结构关于尺度函数和小波函数的内积关系式,即算子。为满足算子正交性,提出基于提升方案的算子自定义小波单元的构造方法,其优点在于可根据问题的需要来设计具有期望特性的小波基。提出基于两尺度误差的自适应算子自定义小波有限元方法,通过向大于误差阈值的局域添加算子自定义小波,实现薄板结构问题的高效求解。算子自定义小波有限元法节省了重新划分网格或提高插值函数的阶次所带来的大量有限元前处理时间,并且实现薄板问题的高效解耦运算。 相似文献
42.
《Current Opinion in Colloid & Interface Science》2001,6(2):140-145
Recent experimental studies on concentrated surfactant systems are reviewed. Particular attention is focused on the transformation from planar lamellar sheets to multilamellar vesicles. It is discussed whether both of these states are thermodynamic stable, or if the MLV is an artifact of shear induced factors. Recent studies includes the dependence on shear, and dependence on salt and cosurfactants, and thereby related lamellar defects. The review include moreover the demonstration that polymeric amphiphiles dramatically enhance the quality of classical surfactants. 相似文献
43.
《Current Applied Physics》2001,1(2-3):203-208
The development of advanced technology based on the interaction of high current pulsed electron beam (HCPEB) with solid materials is very important at present time [R. Stark, J. Christiansen, et al., IEEE Trans. Plasma Sci. 23 (3) (1995) 258–264; T. Witke, A. Lenk, B. Schultrich, IEEE Trans. Plasma Sci. 24 (1) (1996) 61–62]. When the concentrated electron flux are acting on a material, superfast processes such as heating, melting, and solidification, as well as dynamic stresses induced in the processes impart surface layer with improved physical, chemical and mechanical properties unattainable with conventional surface treatment methods. This paper reports on an investigation on pure aluminum treated by “Nadezhda-2” HCPEB device. The extreme surface is melted to a depth of about 1 μm at the input energy density of 3 J/cm2. Craters, micrometers in size, are formed in the melted surface. Vacancy and dislocations are significantly increased near the surface as a result of the electron bombardment. Based on the microhardness distribution measured on the cross-section, it has been established that the thickness of the modified layer is several hundreds of micrometers beneath the surface, significantly greater than that of the heat-affected zone. The experimental results are compared with those obtained by solving numerically the heat and stress equations, with finite difference and finite element methods, taking into account of the processes of melting and changing of physics parameters related to changing temperature. Satisfactory agreement between experimental and theoretical data is obtained. 相似文献
44.
《International Journal of Solids and Structures》2004,41(24-25):6801-6811
The equations of elastic dielectrics with electric field gradient effects are specialized to the case of anti-plane motions of polarized ceramics. A general solution is obtained in polar coordinates. Analytical solutions to the static problems of the potential field of a line source, the capacitance of a circular cylindrical ceramic shell, and the dynamic problem of the dispersion relation of plane waves are obtained to examine the electric field gradient effect. Special attention is paid to the case when the shell is thin and the waves are short. 相似文献
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Geometric structures of a manifold of positive definite Hermite matrices are considered from the viewpoint of information geometry.A Riemannian metric is defined and dual α-connections are introduced.Then the fact that the manifold is ±l-flat is shown.Moreover,the divergence of two points on the manifold is given through dual potential functions.Furthermore,the optimal approximation of a point onto the submanifold is gotten.Finally,some simulations are given to illustrate our results. 相似文献
47.
运用傅里叶变换红外光谱技术研究了正常组织(30例)和细胞株(SW 620),正常细胞核和癌变细胞核的红外光谱特征,为红外光谱诊断结直肠癌奠定了细胞及亚细胞水平的实验基础。将所得光谱图的峰位及峰强比进行统计分析发现:细胞株(SW 620)和癌变细胞核中谱带(2 925,1 240和1 085cm-1)的峰位均向高波数移动(p<0.05),而谱带1 400cm-1的峰位均向低波数移动(p<0.05);细胞株(SW 620)中峰强比(I1 650/I1 460,I1 400/I1 460,I1 240/I1 460,)较正常组织升高(p<0.05),而I1 740/I1 460则降低(p<0.01)。癌变细胞核中(I1 650/I1 460,I1 400/I1 460,I1 240/I1 460)较正常细胞核亦升高(p<0.05).这些差异可作为区别组织良恶性的指标。 相似文献
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以糠酸、甲醇、氢气为原料,采用连续流动固定床微反应器,Pd-Ni/γ-Al2O3为催化剂,使糠酸一步加氢甲酯化生成α-四氢糠酸甲酯.研究了反应的温度,压力,气、液体流速,进料流量等因素对催化反应的影响.结果表明:在1.5MPa,250℃,氢气空速3300 h-1,液体空速3.0 h-1(氢油比为50)时,糠酸转化率为96.6%,四氢糠酸甲酯的选择性97.2.0%,产率94.0%.催化剂稳定性较好,连续运转280小时后未见活性下降.该反应体系活性高,选择性好,反应压力低,催化剂性能稳定,操作简单,产物易分离. 相似文献