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221.
采用间歇式反应器,研究了52 5℃,COH-=5 16mol/L,αk分别为1 45、1 55、1 65的纯铝酸钠和铝酸钾溶液种分过程的晶体粒度分布(PSD)规律。结果表明,在相同的分解条件下,铝酸钠和铝酸钾溶液中晶体的粒度分布随时间的变化有一定差异。铝酸钠溶液PSD曲线的主粒度峰的位置总在铝酸钾溶液的上方;最显著的差异是在分解16h后,铝酸钾溶液的PSD曲线在10~44 774μm处有一个显著的突起峰,而铝酸钠溶液则没有。不同αk的铝酸钠和铝酸钾溶液,这种粒度分布随时间变化的差异相似。 相似文献
222.
Particles in initially well-mixed suspensions subject to inhomogeneous shear flows will migrate and establish a particle concentration gradient and a non-Newtonian velocity profile. In this study, a phenomenological diffusive flux model coupled with flow equations was employed to describe the shear-induced particle migration in a concentrated suspension. The focus of the paper is on the determination of the two phenomenological constants in the diffusive flux model kc and kη. They were determined inversely by employing a least square analysis on the experimental pressure data with different capillary die ratios of length to diameter of the die. The pressures and the flow patterns of the non-Newtonian concentrated suspension were predicted in terms of these two phenomenological constants. The results indicated that particle migration should be accounted for to properly characterize the rheological behaviour of concentrated suspensions. 相似文献
223.
The authors investigated lateralization of spatial learning within the avian hippocampal formation (HF). In Experiment 1, homing pigeons (Columba livia) with unilateral lesions of the right or left HF were trained to locate a goal in a square room containing local landmarks and global room cues. All groups learned the task. During probe trials, when landmarks were rotated or removed, intact pigeons and left HF-lesioned pigeons relied exclusively on global room cues to locate the food goal. Pigeons with right HF lesions were the only group to demonstrably use the landmarks. The results suggest that the right HF is preferentially involved in the representation of global environmental space, whereas only the left HF may be sensitive to local landmarks for navigation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
224.
Shimizu Toru; Bowers Alexia N.; Budzynski Cheri A.; Kahn Meghan C.; Bingman Verner P. 《Canadian Metallurgical Quarterly》2004,118(4):845
Lesion studies have shown that the avian hippocampus plays a crucial role in homing pigeon (Columba livia) navigation. Using the expression of the immediate early gene protein ZENK in intact pigeons, the authors found regional variation in hippocampal activation as a consequence of homing and, necessarily, the behavior and internal states that accompany it. Specifically, pigeons that homed displayed a significant increase in the number of ZENK-labeled cells in the lateral hippocampal formation compared with pigeons that did not home, whereas no difference was seen in the medial hippocampus. Significant changes in ZENK expression were also found in the medial striatum, which resembles the mammalian ventral striatum. The results identify portions of the hippocampal formation and the medial striatum as sites of plasticity associated with homing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
225.
Mechanism of sediment transport is composed of complicated interactions between turbulent flow, particle motion, and bed configurations. Of particular significance is the interaction between turbulence and particle motion, although turbulence measurements of particle-laden two phase flow have been a problem for a long time, especially in the near-wall region. In this study, simultaneous measurements of both the particles and fluid (water) were conducted in particle-laden two phase open channel flows by means of a discriminator particle-tracking velocimetry. The mean velocity and turbulence characteristics for fluid and particles each were examined in comparison with those in clear-water (particle-free) flow, together with previous existing data measured by laser Doppler anemometer and phase Doppler anemometer. The relative velocity and the turbulence modulation, which are the most important topics in two phase-flow approach, were revealed by varying the particle diameter and specific density. The fluid-sweeps are more contributory to the motion of particles than the fluid ejections in the near-wall region. In turn, the particle-sweeps transport the high momentum to the carrier fluid and enhance the turbulence intensities of fluid. 相似文献
226.
We report here the first results of the application of confocal scanning laser microscopy (CSLM) for the study of the microstructure of solid industrial materials. Glass-fibre-reinforced composites, heterogeneous and conductive polymers, homogeneous as well as heterogeneous catalyst (precursor) specimens and soils were examined. We conclude that both the fluorescence and reflection modes of CSLM can yield valuable information. In particular, the optical sectioning capability of CSLM appears to be of great value as it enables one to access the 3-D organization of the specimen without the need for a difficult and time-consuming specimen preparation procedure. However, local obscuration may be an important factor in confocal image formation, limiting the penetration capabilities of the technique for industrial materials. 相似文献
227.
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229.
Masatsugu Takamatsu Michael Barrett Randall J. Charbeneau 《Canadian Metallurgical Quarterly》2010,136(5):527-534
Treatment of storm-water runoff may be necessary before discharge to surface waters. In urban areas, space constraints limit selection of conventional treatment systems, and alternative systems are needed. This research program involves design and laboratory testing of a small footprint nonproprietary detention basin which consists of pipes and box culvert sections with a specialized inlet and outlet system. This system can be placed below grade near the roadway section as part of the conventional drainage system and does not require additional right-of-way. A mathematical model, based entirely on hydraulic principles, is developed to estimate particle removal efficiency of the rectangular detention basin for the treatment of storm-water runoff by extending ideal horizontal tank theory under the condition in which water level is varied. A physical model was built in 1/5 scale to measure particle removal performance and validates the conceptual model. Experiments were performed for steady inflow conditions with different inflow rates, durations, and suspended sediment concentrations. Measured time series outflow suspended sediment concentrations and particle removal efficiency compare well with calculated results from the conceptual model. The outflow particle-size distribution can also be estimated using the conceptual model. 相似文献
230.
本文的目的是研究三种不同的氧化基片(氧化铝、氧化镁及白云石)的润湿特性,以检验Fe-Cr合金在这些基片上的粘附功。利用固滴技术在H2气氛中1823 K下,对氧化基片上液滴(Fe-Cr合金)的接触角进行了研究。随着Cr浓度的增加在氧化铝和白云石基片上的接触角会稍微减小,但不会像在氧化镁基片上变化那么大。在测试基片中,氧化铝基片接触角最大,白云石基片接触角最小。因此,白云石的粘附功最大,这与实际工艺中观察到的结果相符。 相似文献