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81.
Hehuan Cao Jidong Cao Fanghui Wang Shuxian Di Hong Zhu Min Pu Andzhela Bulanova 《International Journal of Hydrogen Energy》2021,46(35):18284-18293
To accelerate the commercialization of fuel cells, many efforts have been made to develope highly active and durable Pt-based catalyst for oxygen reduction reaction (ORR). Herein, PtCu porous nanowires (PNWs) with controllable composition are synthesized through an ultrasound-assisted galvanic replacement reaction. The porous structure, surface strain, and electronic property of PtCu PNWs are optimized by tuning composition, which can improve activity for ORR. Electrochemical tests reveal that the mass activity of Pt0.5Cu0.5 PNWs (Pt/Cu atomic ratio of 1:1) reaches 0.80 A mgPt?1, which is about 5 times higher than that of the commercial Pt/C catalyst. Notably, the improved activity of the porous nanowire catalyst is also confirmed in the single-cell test. In addition, the large contact area with the carrier and internal interconnection structure of Pt0.5Cu0.5 PNWs enables them to exhibit much better durability than the commercial Pt/C catalyst and Pt0.5Cu0.5 nanotubes in accelerated durability test. 相似文献
82.
Ruiyuan Zhang Ting Min Yan Liu Li Chen Wen-Quan Tao 《International Journal of Hydrogen Energy》2021,46(38):20037-20053
Reducing the Platinum (Pt) loading while maintaining the performance is highly desired for promoting the commercial use of proton exchange membrane fuel cells (PEMFCs). Different methods have been adopted to fabricate catalyst layers (CLs) with low Pt loading, including utilizing lower Pt/C catalysts (MA), mixing high Pt/C catalysts with bare carbon black particles (MB), and reducing CL thickness while maintaining high Pt/C ratio (MC). In this study, self-developed pore-scale model is adopted to investigate the performance of the three Pt reduction methods. It is found that MA shows the best performance while MB shows the worst. Then, effects of Pt dispersion are further explored. The results show that denser Pt sites will result in higher local oxygen flux and thus higher local transport resistance. Therefore, MA method, which shows the better Pt dispersion, leads to improved performance. Third, CLs with quasi-realistic structures are investigated. Higher tortuosity resulting from the random pores produces higher bulk resistance along the thickness direction, while MA still exhibits the best performance. Finally, improved CL structures are investigated by designing perforated CL structures. It is found that adding perforations can significantly reduce the bulk transport resistance and can improve the CL performance. It is demonstrated that CL structure plays important roles on performance, and there are still huge potentials to further improve CL performance by increasing Pt dispersion and optimizing CL structures. 相似文献
83.
Lim SuJi Yun Choong-In Song Dahyun Kang Seok-Seong Kim Young-Jun 《Food science and biotechnology》2022,31(9):1145-1155
Food Science and Biotechnology - Oat contains a variety of phenolic compounds, including avenanthramides, which are found only in oats. This study was conducted to establish the quantitative... 相似文献
85.
Yunliang Yue Buwei Wang Nanxi Miao Chao Jiang Hongwei Lu Bowen Zhang Yankai Wu Jie Ren Min Wang 《Ceramics International》2021,47(2):2367-2373
The effects of strain on the magnetic properties of Zr2N MXene have been investigated by the first-principles calculations. The ground state of strain-free Zr2N MXene is intrinsically antiferromagnetic. However, the magnetic state of Zr2N MXene tends to be ferromagnetic when the applied strain is higher than 4%. The transition of magnetic orderings from antiferromagnetism to ferromagnetism under tensile strains can be understood from the Stoner criterion. Besides, the critical temperature (Tc) is about 470 K for the strain-free Zr2N MXene, indicating that the antiferromagnetic ordering can be robust and maintained at room temperature. The Tc of antiferromagnetic states begins to decrease once the strain is exerted. As the FM ordering is favored, however, the Tc then increases with the applied strain. Under 8% tensile strain, the Tc comes to room temperature (300 K). In addition, both the orientation of easy-axis and the magnetic anisotropy energy (MAE) of Zr2N MXene fluctuate with the strain. At the strain of 2%, the MAE reaches the largest (203 μeV per Zr atom), mainly resulting from the spin-orbit interactions between occupied and unoccupied px/py states of Zr atoms. All these tunable and appealing properties make Zr2N MXene desirable for spintronic applications. 相似文献
86.
Zhong-Zheng Jin Min Zha Hai-Long Jia Pin-Kui Ma Si-Qing Wang Jia-Wei Liang Hui-Yuan Wang 《材料科学技术学报》2021,81(22):219-228
In this study,we successfully prepared a Mg-6Zn-0.2Ca alloy by utilizing sub-rapid solidification (SRS)combined with hard-plate rolling (HPR),whose elongation-to-failure increases from ~17 % to ~23 %without sacrificing tensile strength (~290 MPa) compared with its counterpart processed via conven-tional solidification (CS) followed by HPR.Notably,both samples feature a similar refined grain structure with an average grain size of ~2.1 and ~2.5 μm,respectively.However,the high cooling rate of ~ 150 K/s introduced by SRS modified both the size and morphology of Ca2Mg6Zn3 eutectic phase in comparison to those coarse ones under CS condition.By subsequent HPR,the Ca2Mg6Zn3 phase was further refined and dispersed uniformly by severe fragmentation.Specially,the achieved supersaturation containing exces-sive Ca solute atoms due to high cooling rate was maintained in the SRS-HPR condition.The mechanisms that govern the high ductility of the SRS-HPR sample could be ascribed to following reasons.First,refined Ca2Mg6Zn3 eutectic phase could effectively alleviate or avoid the crack initiation.Furthermore,excessive Ca solute atoms in α-Mg matrix result in the yield point phenomenon and enhanced strain-hardening ability during tension.The findings proposed a short-processed strategy towards superior performance of Mg-6Zn-0.2Ca alloy for industrial applications. 相似文献
87.
88.
Jin Wang Mengke Zhang Guanglong Yang Wenwu Song Weiting Zhong Xunyue Wang Minmin Wang Tongming Sun Yanfeng Tang 《Advanced functional materials》2021,31(33):2101532
Highly efficient electrocatalysts composed of earth-abundant elements are desired for water-splitting to produce clean and renewable chemical fuel. Herein, a heteroatomic-doped multi-phase Mo-doped nickel phosphide/nickel sulfide (Mo-NiPx/NiSy) nanowire electrocatalyst is designed by a successive phosphorization and sulfuration method for boosting overall water splitting (both oxygen and hydrogen evolution reactions (HER)) in alkaline solution. As expected, the Mo-NiPx/NiSy electrode possesses low overpotentials both at low and high current densities in HER, while the Mo-NiPx/NiSy heterostructure exhibits high active performance with ultra-low overpotentials of 137, 182, and 250 mV at the current density of 10, 100, and 400 mA cm−2 in 1 m KOH solution, respectively, in oxygen evolution reaction. In particular, the as-prepared Mo-NiPx/NiSy electrodes exhibit remarkable full water splitting performance at both low and high current densities of 10, 100, and 400 mA cm−2 with 1.42, 1.70, and 2.36 V, respectively, which is comparable to commercial electrolysis. 相似文献
89.
90.