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991.
Shi-hua Sang Xiao-ping Li Da-wei Li Rui-zhi Cui Cui Wei 《Russian Journal of Inorganic Chemistry》2018,63(12):1644-1650
Solid-liquid equilibria in the quaternary systems KCl–MgCl2–SrCl2–H2O and NaCl–KCl–SrCl2–H2O at 348 K were measured by the isothermal solution saturation method. The composition of the equilibrium solid phase, solubilities of salts, and densities of saturated solution in the two systems were determined. Phase diagrams, water content diagrams and solution density diagrams of quaternary systems were plotted according to experimental data. The phase diagram of the quaternary system NaCl–KCl–SrCl2–H2O has one invariant point, three univariant curves as the boundary of NaCl, KCl and SrCl2 · 2H2O. This phase diagrams were simple co-saturation type without complex salt and solid solution. For the quaternary system KCl–MgCl2–SrCl2–H2O, one complex salt KCl · MgCl2 · 6H2O (Car) had been found in this system, consisted of five univariant curves, two invariant points and four crystallization regions of MgCl2 · 6H2O (Bis), KCl, SrCl2 · 2H2O and KCl · MgCl2 · 6H2O. And the densities transformation rules were simply discussed. Simultaneously, the solubilities and densities data in invariant point of the quaternary system NaCl–KCl–SrCl2–H2O had been compared with the experimental data of previous researchers. 相似文献
992.
Synthesis of Higher Alcohols via Syngas on Cu/Zn/Si Catalysts. Effect of Polyethylene Glycol Content
Rong-Ji Cui Xing Yan Jin-Chuan Fan Wei Huang 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2018,92(5):884-888
Cu/Zn/Si catalysts with different polyethylene glycol (PEG) content were prepared by a complete liquid-phase method, and characterized by XRD, H2-TPR, N2-adsorption, and XPS. The influence of PEG content on the higher alcohols synthesis from syngas was investigated. The results showed that addition of PEG can influence the texture and surface properties of the catalysts, and therefore affect their activity and product distribution. With an increase in PEG content, BET surface area, Cu crystallite size and surface active ingredient content of the catalysts first increased and then decreased, the CO conversion had similar variation tendency. However, the pore volume and pore diameter of the catalyst increased, and the binding energy of the active component and the content of Cu2O decreased, which resulted in higher catalyst selectivity towards higher alcohols. The highest C2+OH selectivity in total alcohols was 60.6 wt %. 相似文献
993.
Bismuth tellurate nanospheres have been successfully synthesized by a facile hydrothermal route. X-ray diffraction (XRD) shows that the nanospheres are composed of orthorhombic Bi2Te2O7 phase. Scanning electron microscopy (SEM) displays that the diameter of the nanospheres is 100–500 nm. The bismuth tellurate nanospheres (BTS) modified glassy carbon electrode (GCE) has been prepared for the electrochemical detection of L-cysteine (L-CySH). A pair of semi-reversible CV peaks at +0.14 V and–0.84 V, respectively are observed. The BTS modified GCE displays high electrocatalytic activity toward L-CySH and exhibits a linear relationship in the range of 0.0001–2 mM with a detection limit of 0.046 μM in KCl solution. The broad linear range, low detection limit, good reproducibility and stability make the BTS modified GCE valuable for the practical application. 相似文献
994.
995.
Influence of Functional Groups and Modi cation Sites of Metal-Organic Frameworks on CO2/CH4 Separation: A Monte Carlo Simulation Study 下载免费PDF全文
In order to explore the in uence of modification sites of functional groups on landfill gas (CO2/CH4) separation performance of metal-organic frameworks (MOFs), six types of organic linkers and three types of functional groups (i.e. -F, -NH2, -CH3) were used to construct 36 MOFs of pcu topology based on copper paddlewheel. Grand canonical Monte Carlo simulations were performed in this work to evaluate the separation performance of MOFs at low (vacuum swing adsorption) and high (pressure swing adsorption) pressures, respectively. Simulation results demonstrated that CO2 working capacity of the unfunctionalized MOFs generally exhibits pore-size dependence at 1 bar, which increases with the decrease in pore sizes. It was also found that -NH2 functionalized MOFs exhibit the highest CO2 uptake due to the enhanced Coulombic interactions between the polar -NH2 groups and the quadrupole moment of CO2 molecules, which is followed by -CH3 and -F functionalized ones. Moreover, positioning the functional groups -NH2 and -CH3 at sites far from the metal node (site b) exhibits more significant enhancement on CO2/CH4 separation performance compared to that adjacent to the metal node (site a). 相似文献
996.
Electrochemical Study on Hydrogen Evolution and \begin{document}${\rm C}\rm{O}$\end{document} \begin{document}$_\rm{2}$\end{document} Reduction on Pt Electrode in Acid Solutions with Different pH 下载免费PDF全文
Hydrogen evolution reaction (HER) is the major cathodic reaction which competes \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} reduction reaction (\begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} RR) on Pt electrode. Molecular level understanding on how these two reactions interact with each other and what the key factors are of \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} RR kinetics and selectivity will be of great help in optimizing electrolysers for \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} reduction. In this work, we report our results of hydrogen evolution and \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} reduction on Pt(111) and Pt film electrodes in \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} saturated acid solution by cyclic voltammetry and infrared spectroscopy. In solution with pH > 2, the major process is HER and the interfacial pH increases abruptly during HER; \begin{document}${\rm C}\rm{O}_\rm{ad}$\end{document} is the only adsorbed intermediate detected in \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} reduction by infrared spectroscopy; the rate for \begin{document}${\rm C}\rm{O}_\rm{ad}$\end{document} formation increases with the coverage of UPD-H and reaches maximum at the onset potential for HER; the decrease of \begin{document}${\rm C}\rm{O}_\rm{ad}$\end{document} formation under HER is attributed to the available limited sites and the limited residence time for the reduction intermediate (\begin{document}$\rm{H}_\rm{ad}$\end{document} ), which is necessary for \begin{document}${\rm C}\rm{O}_\rm{2}$\end{document} adsorption and reduction. 相似文献
997.
Clustering Algorithms to Analyze Molecular Dynamics Simulation Trajectories for Complex Chemical and Biological Systems? 下载免费PDF全文
Molecular dynamics (MD) simulation has become a powerful tool to investigate the structurefunction relationship of proteins and other biological macromolecules at atomic resolution and biologically relevant timescales. MD simulations often produce massive datasets containing millions of snapshots describing proteins in motion. Therefore, clustering algorithms have been in high demand to be developed and applied to classify these MD snapshots and gain biological insights. There mainly exist two categories of clustering algorithms that aim to group protein conformations into clusters based on the similarity of their shape (geometric clustering) and kinetics (kinetic clustering). In this paper, we review a series of frequently used clustering algorithms applied in MD simulations, including divisive algorithms, agglomerative algorithms (single-linkage, complete-linkage, average-linkage, centroid-linkage and ward-linkage), center-based algorithms (K-Means, K-Medoids, K-Centers, and APM), density-based algorithms (neighbor-based, DBSCAN, density-peaks, and Robust-DB), and spectral-based algorithms (PCCA and PCCA+). In particular, differences between geometric and kinetic clustering metrics will be discussed along with the performances of different clustering algorithms. We note that there does not exist a one-size-fits-all algorithm in the classification of MD datasets. For a specific application, the right choice of clustering algorithm should be based on the purpose of clustering, and the intrinsic properties of the MD conformational ensembles. Therefore, a main focus of our review is to describe the merits and limitations of each clustering algorithm. We expect that this review would be helpful to guide researchers to choose appropriate clustering algorithms for their own MD datasets. 相似文献
998.
999.
Gao Jian Ma Na Tian Jianjun Shen Cong Wang Lili Yu Pengfei Chu Yuanyuan Liu Wei Tan Xiaoyao Li Xifei Yin Zhen 《Journal of Solid State Electrochemistry》2018,22(2):519-525
Journal of Solid State Electrochemistry - One-pot strategy to fabricate N, P co-doping carbon was developed based on the functional ionic liquid (IL) as the N, P, and C precursors. The IL featuring... 相似文献
1000.
在大型仪器分析实验教学中,为了提升学生对基础知识的运用能力,提高学生的动手能力、创新能力,通过引入培训、教学双模式,建立了大型仪器多层次(即基础理论培训、上机操作技术培训和仪器功能应用培训)培训体系。实践证明这种多层次培训体系搭建了学生与专家、学者之间交流的平台。从理论讲解到操作,再到应用的多层次培训体系有效地弥补了大型仪器实验教学中单一教学模式存在的不足,可以很好地培养本科生和研究生的学习兴趣,提高学生分析问题、解决问题的科研能力,同时提升了仪器使用效率,储备了大量仪器方面的专业人才。 相似文献