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101.
《International Journal of Hydrogen Energy》2022,47(7):4386-4393
The rational design of highly effective and low-cost catalysts for oxygen evolution reaction (OER) is of prime importance for the development of water splitting. However, the activity of electrocatalysts still needs enhancement to satisfy the practical application. Herein, we report Co nanoparticles grafted on vanadium nitride (VN) surface via in situ phase separation method by nitriding Co2V2O7 precursor. Benefiting the advantages of abundant active sites of Co, high conductivity and corrosion resistance of VN, the Co/VN achieves incredibly high activity and durability for OER with a low overpotential of 320 mV at a current density of 10 mV cm?2 with a small Tafel slope of 50.4 mV dec?1 and long-term stability. In addition, the in situ Raman further reveals the synergistic effect of Co and VN. Significantly, this study may enrich our knowledge and it can be extended to prepare other interconnected framework structures for the development of OER catalysts. 相似文献
102.
Shuang Chen Chao Yu Zhanfang Cao Xiaoping Huang Shuai Wang Hong Zhong 《International Journal of Hydrogen Energy》2021,46(10):7037-7046
The development of efficient and stable oxygen evolution reaction (OER) catalysts is an ongoing challenge. In order to solve the problem of low oxygen evolution efficiency of the current OER catalysts, a novel material was synthesized by the incorporation of NiFeCr-LDH and MoS2, and its structural and electrochemical properties were also investigated. The introduction of MoS2 improves the electrochemical performance of NiFeCr-LDH. The polarization curve shows that the potential of composite material is only 1.50 V at a current density of 10 mA cm?2, which is far superior to commercial precious metal catalysts. In addition, the stability experiment shows that the composite material has excellent stability, and the current density has little change after 500 cycles. Furthermore, we found that some metal ions, such as Ni, Cr and Mo, exist in the form of high valence on the surface of NiFeCr-LDH@MoS2, which is also conducive to the occurrence of oxygen evolution reaction. 相似文献
103.
S. Sarika S. Abhilash V.S. Sumi S. Rijith 《International Journal of Hydrogen Energy》2021,46(30):16387-16403
A promising electrocatalyst containing variable percentage of V2O5–TiO2 mixed oxide in graphene oxide support was prepared by embedding the catalyst on Cu substrate through facile electroless Ni–Co–P plating for hydrogen evolution reaction. The solvothermal decomposition method was opted for tuning the crystalline characteristics of prepared material. The optimized mixed oxide was well characterized, active sites centres were identified and explained by X-ray diffraction, high resolution tunnelling electron microscopy, scanning electron microscopy coupled with energy dispersive X-ray and X-ray photon spectroscopy analysis. The structural and electronic characteristics of material was done by fourier transform infrared spectroscopy and the electrochemical behaviour of the prepared material was evaluated by using Tafel plot, electrochemical impedance analysis, linear sweep voltammetry, open circuit analysis and chronoamperometry measurements. The results show the enhanced catalytic activity of Ni–Co–P than pure Ni–P plate, due to synergic effect. Moreover, the prepared mixed oxide incorporated Ni–Co–P plate has a high activity towards HER with low over potential of 101 mV, low Tafel slope of 36 mVdec?1, high exchange current density of 9.90 × 10?2 Acm?2. 相似文献
104.
《International Journal of Hydrogen Energy》2021,46(55):27874-27882
Transition metal-based heterostructure materials are considered as promising alternatives to state-of-the-art noble metal-based catalysts toward the oxygen evolution reaction (OER). Herein, for the first time, a simple interface engineering strategy is presented to synthesize efficient electrocatalysts based on a novel CoFe2O4/β-Ni(OH)2 heterogeneous structure for the electrochemical OER. Remarkably, the optimized CoFe2O4/β-Ni(OH)2 electrocatalyst, benefiting from its hierarchical hexagonal heterostructure with strong electronic interaction, enhanced intrinsic activity, and electrochemically active sites, exhibits outstanding OER electrocatalytic performance with a low overpotential of 278 mV to reach a current density of 10 mA cm−2, a small Tafel slope of 67 mV dec−1, and long-standing durability for 30 h. Its exceptional OER performance makes the CoFe2O4/β-Ni(OH)2 heterostructure a prospective candidate for water oxidation in alkaline solution. The proposed interface engineering provides new insights into the fabrication of high-performance electrocatalysts for energy-related applications. 相似文献
105.
本实验以热烫面团为研究对象,通过凯氏定氮法、粒径分析、傅里叶变换红外光谱以及快速黏度分析等手段,研究55、65、75、85 ℃和95 ℃热烫温度下小麦面团中麦谷蛋白大聚体的质量分数、粒径分布、蛋白质二级结构以及面团中淀粉的糊化特性的变化情况。结果表明:随着热烫温度的升高,面团中麦谷蛋白大聚体质量分数呈现显著增大的趋势(P<0.05),小粒径的麦谷蛋白大聚体向中粒径和大粒径转变;面团中蛋白质二级结构发生变化,部分α-螺旋和β-折叠结构转变为β-转角和无规卷曲。同时,面团中淀粉的糊化度随着热烫温度的升高逐渐增大;淀粉的峰值黏度、最低黏度、衰减值、最终黏度、回生值和峰值时间均呈现出减小的趋势,在热烫温度高于75 ℃时,这种变化更加显著。 相似文献
106.
《International Journal of Hydrogen Energy》2021,46(72):35550-35558
The exploration of efficient catalysts toward hydrogen evolution reaction (HER) is still an urgent task. In this paper, Ni/Mo/Cu/C and Ni/Mo/C electrode were obtained by conventional pulse voltammetry, which acted as cathode in microbial electrolysis cells (MECs). The prepared samples are analyzed using SEM, XRD, XPS and electrochemical analysis techniques. Results indicated that the Ni/Mo/Cu coating has a rough and globular structure and presents high current density, a lower Tafel slope of 23.9 mV/dec than 30 mV/dec of Pt, which exceeds the electrochemical activity of Pt electrode. Its remarkably enhanced electrocatalytic activity is attributed to the high surface area, high conductivity as well as synergistic interaction among Ni, Mo and Cu. 相似文献
107.
108.
目的 为比较大豆油体、单甘脂和蔗糖酯三种成分对蛋糕烘焙学特征的影响。方法 本文通过对蛋糕面胚比容、质构,蛋糕面糊比重、黏度和表面气孔特性以及理化指标检测,并对蛋糕进行感官评定进行测试。结果 结果表明,大豆油体最适添加量为4.5%。大豆油体能增加蛋糕的黏度,有助于形成稳定的乳化体系,并且大豆油体蛋糕的酸价、过氧化值和反式脂肪酸检测结果符合国家标准。结论 大豆油体和乳化剂能显著提高豆乳奶油蛋糕的比容,降低硬度,从而改善蛋糕的品质特性。 相似文献
109.
Co-firing NH3 with H2/CO/syngas (SYN) is a promising method to overcome the low reactivity of NH3/air flame. Hence, this study aims to systematically investigate the laminar premixed combustion characteristics of NH3/air flame with various H2/CO/SYN addition loadings (0–40%) using chemical kinetics simulation. The numerical results were obtained based on the Han mechanism which can provide accurate predictions of laminar burning velocities. Results showed that H2 has the greatest effects on increasing laminar burning velocities and net heat release rates of NH3/air flame, followed by SYN and CO. CO has the most significant effects on improving NH3/air adiabatic flame temperatures. The H2/CO/SYN additions can accelerate NH3 decomposition rates and promote the generation of H and NH2 radicals. Furthermore, there is an evident positive linear correlation between the laminar burning velocities and the peak mole fraction of H + NH2 radicals. The reaction NH2 + NH <=> N2H2 + H and NH2 + NO <=> NNH + OH have remarkable positive effects on NH3 combustion. The mole fraction of OH × NH2 radicals positively affects the net heat release rates. Finally, it was discovered that H radicals play an important role in the generation of NO. The H2/CO/SYN additions can reduce the hydrodynamic and diffusional-thermal instabilities of NH3/air flame. The NH3 reaction pathways for NH3–H2/CO/SYN-air flames can be categorized mainly into NH3–NH2–NH–N–N2, NH3–NH2–HNO–NO(?N2O)–N2 and NH3–NH2(?N2H2)–NNH–N2. CO has the greatest influence on the proportions of three NH3 reaction routes. 相似文献
110.
Deok-Hye Park Yo-Seob Kim Sang-Beom Han Woo-Jun Lee Hak-Joo Lee Yong-Soo Lee Sang-Hyun Moon Kyung-Won Park 《International Journal of Hydrogen Energy》2021,46(43):22499-22507
Electrochemical reactions such as the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and methanol oxidation reaction (MOR) are essential for energy conversion applications such as water electrolysis and fuel cells. Furthermore, Pt or Ir-related materials have been extensively utilized as electrocatalysts for the OER, ORR, and MOR. To reduce the utilization of precious metals, innovative catalyst structures should be proposed. Herein, we report a bi-metallic phosphide (Ni2P and PdP2) structure surrounded by graphitic carbon (Ni–Pd–P/C) with an enhanced electrochemical activity as compared to conventional electrocatalysts. Despite the low Pd content of 3 at%, Ni–Pd–P/C exhibits a low overpotential of 330 mV at 10 mA cm?2 in the OER, high specific activity (2.82 mA cm?2 at 0.8 V) for the ORR, and a high current density of 1.101 A mg?1 for the MOR. The superior electrochemical performance of Ni–Pd–P/C may be attributed to the synergistic effect of the bi-metallic phosphide structure and core-shell structure formed by graphitic carbon. 相似文献