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排序方式: 共有691条查询结果,搜索用时 15 毫秒
101.
Guanghui Yuan Huafeng Jin Yanzi Jin Lizhou Wu 《Journal of Solid State Electrochemistry》2018,22(3):693-703
Lithium–sulfur (Li–S) battery is considered as a promising option for electrochemical energy storage applications because of its low-cost and high theoretical capacity. However, the practical application of Li–S battery is still hindered due to the poor electrical conductivity of S cathode and the high dissolution/shuttling of polysulfides in electrolyte. Herein, we report a novel physical and chemical entrapment strategy to address these two problems by designing a sulfur–MnO2@graphene (S–MnO2@GN) ternary hybrid material structure. The MnO2 particles with size of ~ 10 nm are anchored tightly on the wrinkled and twisted GN sheets to form a highly efficient sulfur host. Benefiting from the synergistic effects of GN and MnO2 in both improving the electronic conductivity and hindering polysulfides by physical and chemical adsorptions, this unique S–MnO2@GN composite exhibits excellent electrochemical performances. Reversible specific capacities of 1416, 1114, and 421 mA h g?1 are achieved at rates of 0.1, 0.2, and 3.2 C, respectively. After a 100 cycle stability test, S–MnO2@GN composite cathode could still maintain a reversible capacity of 825 mA h g?1. 相似文献
102.
Higashihara G Inagaki A Akita M 《Dalton transactions (Cambridge, England : 2003)》2008,(14):1888-1898
A series of di- and trinucleating ligands with a 1,3,5-triethylbenzene core connected to N,N-bidentate tethers was synthesized. The ligands readily reacted with monuclear Rh and Pd precursors to give the corresponding di- and trinuclear complexes, which were characterized by using NMR and ESI mass spectroscopy. In the solid state, the trinuclear complexes with ligands having pyridylpyrazolyl tethers adopt the most stable ababab configuration, in which the organometallic fragments are on the same side of the benzene plane. On the other hand, in solution, the linker moieties between the benzene core and the metals are flexible enough to interconvert between other configurations, that is, they exhibit dynamic behavior, and the rotational barrier was dependent on the length of the linkers. From variable temperature (VT) 1H NMR measurements, the rotational barrier for a trinuclear Rh-CO complex with a ligand having methylene linkers was estimated to be approximately 12.6 kcal mol(-1). However, no spectral changes were observed for the ethylene derivative in the temperature range of -60 degrees C to 50 degrees C, indicating that the rotation was not frozen out on the 1H NMR timescale, even at -60 degrees C. 相似文献
103.
A new bifunctional chiral Al(III) complex of BINOL derivative, which contained tert-amine at 3,3′-position of the BINOL, has been developed for the effective enantioselective hydrophosphonylation of aldehydes. A variety of aromatic, heteroaromatic, condensed-ring, α,β-unsaturated, and aliphatic aldehydes were found to be suitable substrates for the reaction, and the desired α-hydroxy phosphonate were obtained in good to excellent yields (up to 99%) with moderate to good enantioselectivities (up to 87% ee) under mild conditions (at 0 °C). A possible catalytic cycle based on the experimental results was proposed. 相似文献
104.
Dr. Shi Tang Dr. Zhi Wang Yanzi Xu Huili Ma Dr. Jia Wang Dr. Christian Larsen Prof. Dongfeng Dang Prof. Ergang Wang Prof. Ludvig Edman 《Angewandte Chemie (International ed. in English)》2023,62(23):e202302874
The emission efficiency of organic semiconductors (OSCs) often suffers from aggregation caused quenching (ACQ). An elegant solution is aggregation-induced emission (AIE), which constitutes the design of the OSC so that its morphology inhibits quenching π–π interactions and non-radiative motional deactivation. The light-emitting electrochemical cell (LEC) can be sustainably fabricated, but its function depends on motion of bulky ions in proximity of the OSC. It is therefore questionable whether the AIE morphology can be retained during LEC operation. Here, we synthesize two structurally similar OSCs, which are distinguished by that 1 features ACQ while 2 delivers AIE. Interestingly, we find that the AIE-LEC significantly outperforms the ACQ-LEC. We rationalize our finding by showing that the AIE morphology remains intact during LEC operation, and that it can feature appropriately sized free-volume voids for facile ion transport and suppressed non-radiative excitonic deactivation. 相似文献
105.
106.
Zejing Xing Xiaodan Gou Prof. Dr. Li-Ping Jiang Prof. Dr. Jun-Jie Zhu Dr. Cheng Ma 《Angewandte Chemie (International ed. in English)》2023,62(39):e202308950
Protein coronas are present extensively at the bio-nano interface due to the natural adsorption of proteins onto nanomaterials in biological fluids. Aside from the robust property of nanoparticles, the dynamics of the protein corona shell largely define their chemical identity by altering interface properties. However, the soft coronas are normally complex and rapidly changing. To real-time monitor the entire formation, we report here a self-regulated electrochemiluminescence (ECL) microscopy based on the interaction of the Ru(bpy)33+ with the nanoparticle surface. Thus, the heterogeneity of the protein corona is in situ observed in single nanoparticle “cores” before and after loading drugs in nanomedicine carriers. The label-free, optical stable and dynamic ECL microscopy minimize misinterpretations caused by the variation of nanoparticle size and polydispersity. Accordingly, the synergetic actions of proteins and nanoparticles properties are uncovered by chemically engineered protein corona. After comparing the protein corona formation kinetics in different complex systems and different nanomedicine carriers, the universality and accuracy of this technique were well demonstrated via the protein corona formation kinetics curves regulated by competitive adsorption of Ru(bpy)33+ and multiple proteins on surface of various carriers. The work is of great significance for studying bio-nano interface in drug delivery and targeted cancer treatment. 相似文献
107.
Yang Zheng Dr. Junhua Chen Chunguo Duan Xinyue Zhang Dr. Xuefang Xu Dr. Qian Gou 《Chemphyschem》2023,24(7):e202200804
The pure rotational spectra of 1-phenylethanol and its monohydrate were measured by using a pulsed jet Fourier transform microwave spectrometer. One conformer of the 1-phenylethanol monomer with the trans form was observed in the pulsed jet. The experimental values of rotational constants of ten isotopologues, including eight mono-substituted 13C and one D isotopologues, allow an accurate structure determination of the skeleton of 1-phenylethanol. For its monohydrate, only one isomer has been observed, of which 1-phenylethanol adopts the trans form and binds with water through an O−H⋅⋅⋅Ow and an Ow−H⋅⋅⋅π hydrogen bond. Each rotational transition displays a doublet with a relative intensity ratio of 1 : 3, due to a hindered internal rotation of water around its C2 axis. This study provides the information on accurate geometry of 1-phenylethanol (PE) and large amplitude motion of water in the PE monohydrate. 相似文献
108.
Z. X. Li W. W. Zhao X. X. Gou X. H. Pu 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2016,90(5):1011-1014
The dissolution behavior of cis-diammineglycolatoplatinum (nedaplatin) in saline, water and glucose were studied by a microcalorimetric method. The integral heats and differential heats of the dissolution were measured to establish the equation for the solute and the heats. The corresponding half-life, kinetic and thermodynamic properties of the nedaplatin solutions were determined. The results show that hydrogen bonds could be generated and the dissolution entropy of nedaplatin in different solvents is negative during the dissolution process, so as to enhance the drug stability, but there is an obvious difference in stability in different solvents. 相似文献
109.
Carnation‐like CuO Hierarchical Nanostructures Assembled by Porous Nanosheets for Nonenzymatic Glucose Sensing 下载免费PDF全文
Carnation‐like CuO hierarchical nanostructures assembled by ultrathin porous nanosheets were successfully fabricated via a facile solvothermal route followed with heat treatment. As‐prepared CuO nanostructures exhibited excellent catalytic activity toward glucose oxidation in the absence of any enzymes. Under the optimized conditions, the CuO‐based enzymeless glucose sensor showed high sensitivity of 3.15 mA mM?1 cm?2, low limit of detection (98 nM, S/N=3), good reproducibility, excellent selectivity and long‐time stability. The superb nonenzymatic glucose sensing performance of the CuO hierarchical nanostructures was attributed to the highly catalytically active sites at the edges and basal planes of the CuO nanosheets, facile transportation of analytes through the abundant mesopores and macropores, robust and stable hierarchical structure. Moreover, the CuO‐based enzymeless glucose sensor showed high accuracy and reliability in comparison with clinical glucometer for quantitative determination of glucose in human blood serum samples. 相似文献
110.
Xin Liu Qinglong Gou Layth Alwan Liang Liang 《The Journal of the Operational Research Society》2016,67(2):187-197
Owing to the limited service capacity of express delivery providers, most online retailers have to reject many orders during hot selling seasons. In this paper, we consider an express delivery service supply chain consisting of an express delivery provider and an online retailer whereby the selling season includes both regular periods and online sales periods. Utilizing a modified newsvendor model, we derive the express delivery provider’s optimal capacity decision and find that the overloading problem cannot be avoided because delivery service cannot be inventoried. To solve such a problem, we introduce an option contract to coordinate the supply chain. By allowing the online retailer to book the capacity, the express delivery provider can rent capacity from a third party in advance. Results show this approach can mitigate the problem significantly. We also extend our model to a supply chain consisting of a delivery provider and two retailers. 相似文献