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651.
基于南海北部中生界勘探面临的复杂地震地质条件,为改善该海域地震勘探难点区的资料质量,本文设计出6400in3的Bolt长寿枪震源,其特点是震源子波输出峰值和低频段能量得到加强,低频端由8Hz拓展到6Hz。通过对野外试验及实际海上地震勘探数据采集的效果的分析、对比,证实所设计的震源适用于南海北部中生界的油气资源探测。  相似文献   
652.
Layout optimization with ON/OFF information of magnetic material in finite elements is one of the most attractive tools in the initial conceptual and practical design of electrical machinery for engineers. Heuristic algorithms based on random search allow engineers to define general‐purpose objects. However, there are many iterations of finite element analysis, and it is difficult to achieve a practical solution without island and void distribution by using a direct search method, such as simulated annealing (SA), genetic algorithm (GA), and so on. This paper presents a layout optimization method based on GA. The proposed method can arrive at a practical solution by means of multistep utilization of the GA, and the convergence speed is considerably improved by using it in combination with reduction of the design space. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(3): 19‐30, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22290  相似文献   
653.
Vascular endothelial cells cover the luminal surface of blood vessels and contribute to the prevention of vascular disorders such as atherosclerosis. Metallothionein (MT) is a low molecular weight, cysteine-rich, metal-binding, inducible protein, which protects cells from the toxicity of heavy metals and active oxygen species. Endothelial MT is not induced by inorganic zinc. Adequate tools are required to investigate the mechanisms underlying endothelial MT induction. In the present study, we found that an organoantimony compound, tris(pentafluorophenyl)stibane, induces gene expression of MT-1A and MT-2A, which are subisoforms of MT in bovine aortic endothelial cells. The data reveal that MT-1A is induced by activation of both the MTF-1–MRE and Nrf2–ARE pathways, whereas MT-2A expression requires only activation of the MTF-1–MRE pathway. The present data suggest that the original role of MT-1 is to protect cells from heavy metal toxicity and oxidative stress in the biological defense system, while that of MT-2 is to regulate intracellular zinc metabolism.  相似文献   
654.
In this paper, we investigate common-mode (CM) noise caused by a connection to a two-dimensional finite-size ground plane. Numerical calculations are conducted to visualize the time variation of potentials that leads to CM noise. A connection of the signal line to the ground plane, which is conventionally used in circuits, causes an imbalance in the circuit that makes the potential of the ground plane fluctuate, which results in CM noise. CM noise does not occur in a symmetric three-line circuit because the potential of the middle line is always kept at 0 V. Furthermore, the middle line prevents an externally induced potential fluctuation of the ground plane from being converted to a normal-mode voltage (i.e., CM noise).  相似文献   
655.
Local structures around a bismuth ion in bismuth-doped silica glasses (BiSG) are analyzed using a Bi LIII X-ray absorption fine structure (XAFS). The XAFS spectrum of crystalline α-Bi2O3 was also measured for comparison with BiSG whose first peaks are about 0.1 Å less than α-Bi2O3 in radial structure functions. According to curve-fitting results using FEFF 8.2, the Bi–O distances of the first and second neighboring coordination spheres are estimated to be 2.1 and 2.3 Å, respectively. The former corresponds to Bi5+–O bonding and the latter to Bi3+–O bonding compared with the Bi–O distances in typical crystals including Bi3+ and Bi5+ ions. The above results show that Bi ions in BiSG exist as both Bi3+ and Bi5+ states, which is also supported by X-ray absorption near the edge structure spectra of BiSG.  相似文献   
656.
When particles are transported in pipelines, they acquire electrostatic charges as they come into contact with the pipe wall. Charged particles can cause problems such as particle agglomeration, blockage, and explosion. Understanding the particle charge can help to prevent these issues. This study investigates a technique for predicting the particle charge in a straight pipe of any given length, as well as the pipe length at which electrostatic equilibrium occurs, through experimentation in a short 1‐m pipe section. Experimentation with five different types of particles and four pipe wall materials at longer pipe lengths were used to validate the technique. This predictive technique is applicable to a range of particle shapes and sizes under the restriction that charge transfer is due to impact charging. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2308–2316, 2013  相似文献   
657.
The oxidation processes of linoleic acid (LA) in the presence of l-ascorbic acid or saturated acyl l-ascorbate additives were measured at various temperatures and molar ratios of the additive to LA. Higher oxidative stability of LA was observed at higher additive levels for all additives. The addition of the ascorbates lengthened the induction period for the oxidation of LA. An autocatalytic kinetic rate equation was used to model the oxidation processes of LA mixed with the ascorbates, and the dependence of the rate constant, k, on acyl-chain carbon number was determined. At any temperature, the use of ascorbate additives decreased the k value for LA, and there was a slight tendency for k values to decrease with increasing acyl-chain length. The apparent activation energy, E a, and the frequency factor, k 0, for the rate constant were determined from Arrhenius plots. The calculated E a and k 0 values also decreased with increasing ascorbate acyl-chain length.  相似文献   
658.
Yunoki K  Yasui Y  Hirose S  Ohnishi M 《Lipids》2005,40(4):361-367
FA components of 11 mustsmade from grape cultivars grown for making red wine in various regions of Japan and of wines made from the musts were compared to elucidate variety-dependent characteristics and to clarify their effect on FA ethyl ester (FAEE) formation in wine. Sixteen FA with carbon chain lengths from 12 to 26 were detected in all musts, with palmitic, linoleic, and linolenic acids generally predominating. Higher levels of linoleic acid were found in musts from a cold region (Hokkaido), and higher levels of oleic acid occurred in musts from a warm region (Honshu). Moreover, the unsaturation indexes (1.31–1.56) of five grape musts from the cold region showed significant differences among varieties, corresponding to the grapevines’ degree of cryotolerance. The FA levels (610–6,610 nmol/100 mL) of all wines were extremely low (1.2–12.8%) compared with those of must, but the FA compositions were similar to those of must. Additionally, significant amounts of FAEE, possibly derived from yeast activity, were found in wines by using a solid-phase extraction method. The amounts of FAEE in wine significantly differed among samples (245–904 nmol/100 mL) and were inversely correlated with the percentage of linoleic acid in musts (R=−0.883). Thus, higher linoleic acid levels in must may be related to lower FAEE formation by yeast.  相似文献   
659.
Melting points of poly(vinyl alcohol) (PVA) gels obtained by repeated freezing/thawing cycles of the solutions in mixed solvents of water and dimethyl sulfoxide (DMSO) were measured. PVA solutions in 1–30 and 90 vol % DMSO froze at ?40°C. The melting point of a gel increased with an increase in freezing/thawing cycles for all the solutions frozen and with an increase in freezing time in 10–30 vol % DMSO. The solutions in 1–5 vol % DMSO gelled even at very low polymer concentration of 1.0 g/dL by repeated freezing/thawing. The melting point of all the gels with a 5% polymer concentration reached ca. 73°C after 14 freezing/thawing cycles except for the gels in 90 vol % DMSO. However, the melting point of the gels with the same polymer concentration prepared at ?40°C using an unfrozen mixed solvent in 60 vol % DMSO was ca. 77°C and the largest. The maximum apparent enthalpy of fusion of the gels prepared by repeated freezing/thawing was ca. 40 kcal/mol. The gels in 90 vol % DMSO were transparent independent of cycles where as those in 1–80 vol % DMSO were opaque. The degree of opaqueness increased with decreasing DMSO content.  相似文献   
660.
Hydrogen perm-selective membranes composed of Pd nanoparticles were investigated. The nanoparticles were prepared by ultrasonic reduction from PdII ions, and then deposited on a substrate disc with electrophoresis technique. These electrophoretic membranes have shown high performance of perm-selectivity for H2 with separation factor α = 3.85, under room temperature.  相似文献   
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