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91.
长轴表面激光淬火变形与控制 总被引:1,自引:0,他引:1
应用激光淬火强化技术控制长轴的淬火变形,分析了激光淬火变形的原因和影响因素。研究结果表明,激光淬火不仅可使长轴振摆变形量控制在很小的范围内,而且可将已变形的长轴校直到很高的精度。 相似文献
92.
The existing intelligent fault diagnosis techniques of bevel gear focus on single-sensor signal analysis under the steady operation condition. In this study, a new method is proposed based on ensemble deep transfer learning and multisensor signals to enhance the fault diagnosis adaptability and reliability of bevel gear under various operation conditions. First, a novel stacked autoencoder(NSAE) is constructed using a denoising autoencoder, batch normalization, and the Swish activation function. Second, a series of source-domain NSAEs with multisensor vibration signals is pretrained. Third, the good model parameters provided by the source-domain NSAEs are transferred to initialize the corresponding target-domain NSAEs. Finally, a modified voting fusion strategy is designed to obtain a comprehensive result. The multisensor signals collected under the different operation conditions of bevel gear are used to verify the proposed method. The comparison results show that the proposed method can diagnose different faults in an accurate and stable manner using only one target-domain sample, thereby outperforming the existing methods. 相似文献
93.
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95.
Canchen Sun Yuanyuan Wang Bin Wang Yanxia Cao Jianfeng Wang Yanyu Yang Wanjie Wang 《大分子材料与工程》2021,306(5):2000813
Here, zinc-neutralized ethylene propylene diene monomer (EPDM) ionomers with different neutralization levels are prepared through melt blending, and are then incorporated with polyamide 1012 (PA1012) to fabricate PA1012/EPDM ionomer blends. Interestingly, complex crosslinking networks are formed in the blends due to the construction of sacrificial bonds (Zn2+-carboxyl, Zn2+-amide). The as-formed network structure and sacrificial bond endow the PA/EPDM blends with largely enhanced toughness (16 times higher than that of neat PA), as well as balanced strength and stiffness. Meanwhile, the rheological behaviors of PA1012/EPDM ionomer blends indicate their relative low melting viscosity, which can avoid the processing shortcomings of plastics toughened with rubber. Moreover, PA1012/EPDM ionomer blends show obvious gelation behavior, and a maximum notched Izod impact strength exhibited at the gel point, in which unique double network structure can be observed obviously, indicating that there is a corresponding correlation between the rheological and mechanical parameters. Furthermore, the supper-toughening mechanism of PA1012/EPDM ionomer blends at gel point is explored, which origins from the large deformation and cavitation of rubber particles and the destruction of special double network morphologies. This study provides a novel and effective strategy to fabricate PA materials with outstanding toughness and excellent strength simultaneously. 相似文献
96.
Junpeng Xiong Weili Shao Ling Wang Chen Cui Yurui Jin Hongqin Yu Pengju Han Yanfei Gao Fan Liu Qingqing Ni Jianxin He 《大分子材料与工程》2021,306(11):2100371
Recently, because of the outbreak of COVID-19, the demand for various types of filter elements in protective materials has increased globally. Furthermore, new requirements for the filtration performance of PM2.5 liquid (oil) particles have been put forward. In this work, Superhydrophobic and superoleophobic composite nanofibers with excellent filtration capacity for oil and salt particles are developed through the modification of polyacrylonitrile (PAN) by fluoro-polyurethane (FPU) doping. The results show that the PAN/FPU composite nanofibers doped with 9 wt% FPU has a uniform fiber morphology with a diameter of 240 ± 30 nm. Compared to the pure PAN nanofibers, the water-based contact angle of PAN/FPU increases from 90 ± 5° to 151 ± 5°, and the oil-based contact angle increases from 58 ± 2° to 152 ± 3°. Importantly, at a high flow rate of 95 L min−1, the filtration efficiency of the PAN/FPU nanofiber membrane for 0.3 µm oil particles increases from 92 ± 1% to 99.2 ± 0.1%. After cyclic loading, the filtration efficiency of 0.3 µm oil particles remains above 98%. Meanwhile, the filtration efficiency for 0.3 µm salt particles remains at 98.23 ± 0.1%. The PAN/FPU nanofiber membrane developed in this work is effective in applications and has good market prospects as a protective filtration material. 相似文献
97.
Dr. Xicheng Liu Mingxiao Shao Congcong Liang Jinghang Guo Guangxuan Wang Xiang-Ai Yuan Zhihong Jing Laijin Tian Prof. Dr. Zhe Liu 《Chembiochem : a European journal of chemical biology》2021,22(3):557-564
A series of half-sandwich structural iridium(III) phenanthroline (Phen) complexes with halide ions (Cl−, Br−, I−) and pyridine leaving groups ([(η5-CpX)Ir(Phen)Z](PF6)n, Cpx: electron-rich cyclopentadienyl group, Z: leaving group) have been prepared. Target complexes, especially the Cpxbiph (biphenyl-substituted cyclopentadienyl)-based one, showed favourable anticancer activity against human lung cancer (A549) cells; the best one ( Ir8 ) was almost five times that of cisplatin under the same conditions. Compared with complexes involving halide ion leaving groups, the pyridine-based one did not display hydrolysis but effectively caused lysosomal damage, leading to accumulation in the cytosol, inducing an increase in the level of intracellular reactive oxygen species and apoptosis; this indicated an anticancer mechanism of oxidation. Additionally, these complexes could bind to serum albumin through a static quenching mechanism. The data highlight the potential value of half-sandwich iridium(III) phenanthroline complexes as anticancer drugs. 相似文献
98.
近年来铈(Ce)基脱硝催化剂成为低温脱硝领域的研究热点,按载体类型可分为金属氧化物催化剂、二氧化钛载体催化剂、分子筛载体催化剂、活性炭及氧化铝载体催化剂等。按催化剂种类分别介绍了掺杂改性、制备工艺、反应条件等对催化剂性能的影响,并阐述了可能的原因机理。目前,铈基催化剂大多处于实验室阶段,工业化应用尚存在问题,尤其作为低温脱硝催化剂,活性中心堵塞问题更加突出,并且催化剂成本较高。未来可从催化剂制备工艺入手解决催化剂成型问题,以实现工业应用。同时探讨催化剂中毒机理,进一步提升其抗中毒能力。另外,寻求适宜的材料与铈掺杂组合,达到高效脱硝和经济效益最大化。 相似文献
99.
采用水热法制备GRQD-NiCo2O4复合物,利用XRD、SEM及TEM分析其微结构,并探讨其作为DMFC阳极催化剂使用时的电化学性能。微结构分析表明所得GRQD-NiCo2O4复合物皆为具NiCo2O4单一相的尖晶石结构,且GRQD质量浓度高于0.25 g/mL后表面形貌将转变GRQD与NiCo2O4相互结合的状态。电化学分析表明添加GRQD可有效增强NiCo2O4的导电性并提升其电化学稳定性,其中GRQD质量浓度为0.25 g/mL时所得样品经500次循环测试后电流密度约为77.5 A/g,与循环5次后相比其电流密度剩余量最大(约为69.7%),该样品作为DMFC阳极催化剂使用时性价比最佳。 相似文献
100.
Si及变质处理对Mg2Si/Mg复合材料的影响 总被引:1,自引:1,他引:1
分析了Mg-Si二元合金直接原位形成Mg2Si/Mg复合材料的过程,研究了Si含量以及变质处理对复合材料组织和性能的影响。试验结果表明,随着合金中Si含量的增加,合金的流动性降低,复合材料中原位Mg2Si的数量增多,树枝晶形态更为发达;对优化的Mg-8Si合金,进行混合稀土(MM)和Sb变质处理,可明显改善Mg2Si的形态和分布,但Sb变质的效果要好于MM。合金经质量分数为1.2%的Sb变质处理后,Mg2Si以颗粒状均匀分布在Mg基体中,从而使复合材料具有较好的耐磨性。 相似文献