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91.
The retinal projections to gastrin-releasing peptide (GRP)-expressing neurons in the rat suprachiasmatic nucleus (SCN) were investigated by double immunofluorescence and immunoelectron microscopy. Optic nerve terminals labeled by cholera toxin B subunit (CTb) which was transported from the retinal ganglion cells were intermingled with GRP-immunoreactive cell bodies and processes in the ventrolateral portion of the SCN. Ultrastructural analysis revealed that CTb-immunoreactive retinal terminals made synaptic contacts with GRP-immunoreactive dendritic processes. These results demonstrated that photic information is directly input from the optic nerve to GRP neurons in the SCN and these GRP neurons may be involved in circadian entrainment by light.  相似文献   
92.
研究了内扩散法Nb3Sn多芯线材随温度和磁场变化的磁化曲线及磁化率,绘出了磁化量-磁场-温度(M-H-T)的三维临界曲面,归一化后的磁化曲线基本符合Kramer拟和方程。计算得到的Nb3Sn多芯线材有效直径比芯线的原始几何尺寸要大,其原因在于微观结构中存在着“桥梁”,分析表明,多余的磁滞损耗来自于“桥梁”。交流磁化率和X’和X″在给定频率和背景磁场下,随交流振幅的变化很小,在给定交流振幅下,随交流  相似文献   
93.
A mirror-polishing technique for fluorocarbon polymer surfaces using high-precision diamond cutting tools was developed. The goal of this technique was the reduction of ultratrace elemental analysis contamination levels of containers fabricated from such mirror-polished materials. Remarkably smooth inner surfaces with degrees of flatness of 0.1 μm peak-to-valley (PTV) for containers fabricated from mirror-polished PTFE materials were obtained, in contrast to degrees of surface flatness of more than 30 μm PTV for commercially available PTFE containers. (Here, PTV denotes the difference between the highest peak and deepest valley in a scanned area of 10 × 10 μm.) Extractable impurity levels for mirror-polished PTFE container surfaces were reduced by more than 1 order of magnitude relative to those of unpolished PTFE containers. The surface conditions of the PTFE containers were observed by atomic force and scanning electron microscopy. The microphotographs so obtained suggest that the degree of surface smoothness of the containers is proportional to their ultratrace metallic contamination levels.  相似文献   
94.
Improved High-Q Dielectric Resonator with Complex Perovskite Structure   总被引:1,自引:0,他引:1  
Microwave characteristics of the system Ba(Zn1/3Ta2/3)O3-BaZrO3 were investigated. Ba(Zn,Ta)O3 has a perovskite pseudocell and hexagonal superstructure; the superstructure was not formed after addition of BaZrO3. Both sintering and crystallization of Ba(Zn,Ta)O3-BaZrO3 were accelerated compared to those of Ba(Zn,Ta)O3 alone, and the microwave Q value was also improved. The material optimized for the dielectric resonator, Ba(Ni,Ta)O3-Ba(Zr,Zn,Ta)O3, has a dielectric constant of 30, Q value of 10000 at 10 GHz, and temperature coeficient of resonant frequency of 0 ppm/°C.  相似文献   
95.
A systematic approach for the steady-state operation analysis of chemical processes is pro-posed.The method affords the possibility of taking operation resilience into consideration during thestage of process design.It may serve the designer as an efficient means for the initial screening ofalternative design schemes.An ideal heat integrated distillation column(HIDiC),without any reboileror condenser attached,is studied throughout this work.It has been found that among the various va-riables concerned with the ideal HIDiC,feed thermal condition appears to be the only factor exertingsignificant influences on the interaction between the top and the bottom control loops.Maximuminteraction is expected when the feed thermal condition approaches 0.5.Total number of stages andheat transfer rate are essential to the system ability of disturbance rejection.Therefore,more stagesand higher heat transfer rate ought to be preferred.But,too many stages and higher heat transfer ratemay increase the load of the compres  相似文献   
96.
By manipulating process parameters, BaTiO3 nanoparticles with tunable size were successfully prepared by flame-assisted spray pyrolysis (FASP) from an aqueous solution of barium acetate and titanium-tetra-isopropoxite. Particle size was controlled over a wide range (from about 23 to 71 nm) by varying the concentration of precursor and methane flow rate. Flame temperature was a key factor in producing particles with a narrow size distribution. The BaTiO3 nanoparticles were cubic in crystal structure, dense, spherical and softly agglomerated. The particles contained OH, carboxyl and CO2 bonding groups that could be completely removed by post-heat treatment. At room temperature, BaTiO3 pellets had relatively high dielectric constants (2578.8–3611.8) with loss factors ranging from 2.6% to 7.1% at the frequency of 1 kHz. The results of this study indicate that BaTiO3 nanoparticles can be fabricated using continuous and industrially applicable FASP.  相似文献   
97.
Reinforcement learning (RL) for robot control is an important technology for future robots since it enables us to design a robot’s behavior using the reward function. However, RL for high degree-of-freedom robot control is still an open issue. This paper proposes a discrete action space DCOB which is generated from the basis functions (BFs) given to approximate a value function. The remarkable feature is that, by reducing the number of BFs to enable the robot to learn quickly the value function, the size of DCOB is also reduced, which improves the learning speed. In addition, a method WF-DCOB is proposed to enhance the performance, where wire-fitting is utilized to search for continuous actions around each discrete action of DCOB. We apply the proposed methods to motion learning tasks of a simulated humanoid robot and a real spider robot. The experimental results demonstrate outstanding performance.  相似文献   
98.
This paper proposes a brace whose strength, plastic deformation capacity remaining after yield and energy absorption capacity under seismic loading can be easily evaluated for performance-based seismic design. The proposed brace consists of a slender rod with tensile-connected ends incorporating a beveled washer and wedge. There is no buckling in the brace. The wedge slides between a washer and stand so as to prevent brace looseness due to axial plastic deformation under repeated loading.To verify the brace’s mechanism and performance, repeated horizontal loading tests were performed on a one-story bay frame with a tensile-connected brace having a wedge device.Results and conclusions obtained from the loading tests are summarized as follows.(1) Perfect elasto-plastic hysteresis was observed until the wedge’s sliding displacement reached its maximum. (2) Story shear stiffness, strength and energy absorption capacity were easily evaluated. (3) Plastic deformation capacity remaining after an earthquake can be evaluated by checking the wedge’s total sliding displacement. (4) Performance-based design can be easily achieved with this brace.  相似文献   
99.

In the manufacturing of nanometer-sized material particlulates by aerosol gas-to-particle conversion processes, it is important to analyze how the gas-phase chemical reaction, nucleation, agglomeration, and sintering rates control the size distribution and morphology of particles. In this study, titania particles were produced experimentally by the thermal decomposition of titanium tetraisopropoxide (TTIP) and oxidation of titanium tetrachloride (TiCl 4 ) using a laminar flow aerosol reactor. The effect of reaction temperature on the size and morphology of the generated particles was investigated under various conditions. The size distributions of agglomerates were measured using a DMA/CNC system. The size distributions of primary particles were measured using TEM pictures of the agglomerates sampled by a thermophoretic aerosol sampler. In order to model the growth of both agglomerates and primary particles simultaneously, a two-dimensional discrete-sectional representation of the size distribution was employed, solving the aerosol general dynamic equation for chemical reaction, agglomeration, and sintering. Qualitative agreement between the experimentally observed results and the simulation are satisfactory for the large variations in reactor temperature explored.  相似文献   
100.
A new method was proposed to measure the thermal conductivity of liquids with infinitesimal samples, which are much smaller than those required in conventional methods. The method utilizes a micro-beam-type MEMS sensor fabricated across a trench on a silicon substrate. Numerical analysis of heat conduction within and around a uniformly heated sensor showed that the temperature of a 10 μm long sensor reached a steady state within approximately 0.1ms, after the start of heating. It was also revealed that the average temperature of the sensor at the steady state was higher in liquids with lower thermal conductivity. These results demonstrate a new idea of measuring the thermal conductivity of liquids within an extremely short time at a steady state before the onset of natural convection.  相似文献   
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