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951.
广西车田沸石用于吸附室内甲醛的应用研究 总被引:1,自引:0,他引:1
本文采用不同的热处理方法和NaCl、H2SO4、HCl、NaOH等无机试剂以及十六烷基三甲基溴化氨(HDTMA)、十二烷苯磺酸钠等有机试剂对广西车田天然沸石分别进行改性,并对不同改性沸石对甲醛的吸附性能结果进行了比较分析。 相似文献
952.
M. C. Nataraja T. S. Nagaraj S. Bhavanishankar B. M. Ramalinga Reddy 《Materials and Structures》2007,40(6):543-552
This paper presents an experimental investigation to advance a stepwise procedure to proportion plain and slag concrete mixes
with burnt coal cinder waste as coarse aggregate. When typical strength of coarse aggregate in concrete is lower than the
concrete strength required, conventional methods such as British Method, ACI and country’s standard code cannot be used directly
since failure of concrete is predominantly by aggregate crushing. To analyze the data, concrete, for simplicity, is regarded
as two phase composite of cement mortar matrix and coarse aggregate. With the concrete and constituent cement mortar matrix
strengths and their respective volume fractions as input parameters, the typical strength of coarse aggregate in concrete
is determined from linear law of mixtures. Using again the same law, the cement mortar matrix strength required for higher
or at par to that of the typical aggregate strength is calculated. To arrive at water–cement ratio for matrix strength, the
Generalized Abrams’ law is employed. 相似文献
953.
B.L. Wang 《Engineering Fracture Mechanics》2007,74(9):1456-1467
The accumulated plastic displacement criterion for crack propagation in traditional materials is extended to develop equations to predict the fatigue crack growth of ferroelectric ceramics subjected to combined electromechanical loads. The crack-line is perpendicular to the poling direction of the medium. An electric saturation zone and a stress saturation zone are assumed to develop at the crack tips when the medium is subjected to external electromechanical loads. This assumption makes it possible to obtain the accumulated plastic deformation in closed form. A fatigue crack growth law, which is a fourth-power function of the effective stress intensity factor, similar to the well-known Paris law, is derived. Graphical results for the effect of electric load on the effective crack tip stress intensity factor and crack growth rate are provided. 相似文献
954.
Yih-Cherng Chiang 《Engineering Fracture Mechanics》2007,74(10):1602-1616
A matrix cracking model is developed based upon Coulomb friction law instead of a constant frictional shear stress usually assumed in the matrix cracking analyses. A Lamé formulation incorporated with Coulomb friction law is adopted to solve the elastic states of fiber/matrix stress-transfer through a frictionally constrained interface in the slipping region and a modified shear lag model is applied to evaluate the elastic responses in the intact region. By using an energy balance approach, the critical stress for propagating a semi-infinite fiber-bridged crack in a unidirectional fiber reinforced composite is formulated in terms of the frictional coefficient rather than the frictional shear stress usually equated in the matrix cracking stress formulations. The critical stress for matrix cracking and the corresponding stress distributions calculated by the present Coulomb friction model will be compared with those predicted by the constant frictional shear stress models. The effect of Poisson contraction caused by stress redistribution between the fiber and matrix on the matrix cracking mechanics will be shown and discussed in the present analysis. 相似文献
955.
介绍了脉搏血样饱和度检测的理论基础与重要的临床应用价值。提出了一种基于CMOS影像传感器的脉搏血氧饱和度监测系统,用CMOS传感器阵列取代了传统血氧仪中的光敏探测,实现了血氧饱和度及脉搏波的无接触测量。阐述了其在组织发育、伤口诊断、病变的提前预测等场合的潜在应用价值。实验结果表明,由于摄像头不能够有效屏蔽外界光源噪声的干扰,所设计样机较传统的血氧仪测得的饱和度值偏低,误差偏大,从而进一步提出减小误差提高精度的方案构想。 相似文献
956.
957.
利用函数单向S-粗集对偶,结合系统规律生成,提出了开环控制系统的扰动识别准则,并给出了开环控制系统扰动识别的结构图和具体实现过程.最后通过一个实例表明该方法有效. 相似文献
958.
陈月顺 《武汉理工大学学报(材料科学英文版)》2007,22(2):354-357
The influence of reinforced bar corrosion on the bond degradation in lightweight concrete was studied. Accelerated constant current corrosion tests were performed on lightweight reinforced concrete samples, and the influential factors, such as protective layer thickness, reinforced bar diameter and corrosive level were investigated. The constant current step method was used to measure the electric resistance of the concrete protective cover, which was used to characterize the corrosion level of the rebar. Experimental results indicated that the corrosive resistance increased with increasing the cover dimension and decreasing the reinforced bar diameter, and the rate of decrease in the specimen impedance after cracking depended on the cover dimension. A new medium was offered for the further research on the performance degradation of corrosion lightweight concrete. 相似文献
959.
Calculating models of mass action concentrations for NaBr(aq), LiNO3(aq), HNO3(aq), and KF(aq) binary solutions 总被引:1,自引:0,他引:1
Hanjie Guo Weijie Zhao Xuemin Yang 《北京科技大学学报(英文版)》2007,14(3):204-211
The calculating models of mass action concentrations for electrolyte aqueous solutions NaBr-H2O, LiNO3-H2O, HNO3-H2O, and KF-H2O have been developed at 298.15 K and their molalities ranging from 0.1 mol/kg to saturation according to the ion and molecule coexistence theory as well as mass action law. The calculated mass action concentration is based on pure species as the standard state and the mole fraction as the concentration unit, and the reported activities are usually based on infinite dilution as the standard state and molality as the concentration unit. Hence, the calculated mass action concentration must be transformed to the same standard state and concentration unit. The transformation coefficients between calculated mass action concentrations and reported ac- tivities of the same component fluctuate in a very narrow range. Thus, the transformed mass action concentrations not only agree well with reported activities, but also strictly obey mass action law. The calculated results show that the new developed models can embody the intrinsic structure of investigated four electrolyte aqueous solutions. The results also indicate that mass action law has its wide- spread applicability to electrolyte binary aqueous solutions. 相似文献
960.
传统的法律信仰的缺失,现代法律信仰的难以形成,我国法治正面临着法律信仰的危机。“法律必须被信仰,否则它将形同虚设”。公众对法律的信仰是中国法治化进程的内在驱动力。因此,透过我国公民的法治信仰现实,分析法律信仰危机产生的原因以找到重塑法律信仰的途径已经成为中国法治的当务之急。 相似文献