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951.
Hydrothermal reaction of copper(II) acetate, 2,2′-bipyridine (bipy) and NH4VO3 at 170 °C lead to a new layered polyoxovanadate with organically covalent-bonded copper(II) complex, Cu2(bipy)2V6O17 (1). Cu2(bipy)2V6O17 (1) is a new copper(II) vanadium(V) oxide featuring a new layered architecture, in which the V2O7 dimeric units and the cyclic tetranuclear V4O12 cluster units are interconnected via corner sharing into a unique one-dimensional {V6O17}4− anionic chain, such chains are further bridged by {Cu(bipy)}2+ complex cations into a 010 organic–inorganic hybrid layer. 相似文献
952.
Xinjian Ji Dr. Yongzhen Li Dr. Liqi Xie Prof. Dr. Haojie Lu Prof. Dr. Wei Ding Prof. Dr. Qi Zhang 《Angewandte Chemie (International ed. in English)》2016,55(39):11845-11848
Radical S‐adenosyl‐l ‐methionine (SAM) enzymes utilize a [4Fe‐4S] cluster to bind SAM and reductively cleave its carbon–sulfur bond to produce a highly reactive 5′‐deoxyadenosyl (dAdo) radical. In almost all cases, the dAdo radical abstracts a hydrogen atom from the substrates or from enzymes, thereby initiating a highly diverse array of reactions. Herein, we report a change of the dAdo radical‐based chemistry from hydrogen abstraction to radical addition in the reaction of the radical SAM enzyme NosL. This change was achieved by using a substrate analogue containing an olefin moiety. We also showed that two SAM analogues containing different nucleoside functionalities initiate the radical‐based reactions with high efficiencies. The radical adduct with the olefin produced in the reaction was found to undergo two divergent reactions, and the mechanistic insights into this process were investigated in detail. Our study demonstrates a promising strategy in expanding radical SAM chemistry, providing an effective way to access nucleoside‐containing compounds by using radical SAM‐dependent reactions. 相似文献
953.
954.
A monolithic stationary phase was prepared in a single step by in situ copolymerization of iso-butyl methacrylate (IBMA), ethylene dimethacrylate (EDMA), and N,N-dimethylallylamine (DMAA) in a binary porogenic solvent consisting of N,N-dimethylformamide (DMF) and 1,4-butanediol. As the frame structures of monoliths, the amino groups are linked to support the EOF necessary for driving the mobile phase through the monolithic capillary, while the hydrophobic groups are introduced to provide the nonpolar sites for the chromatographic retention. To evaluate the column performance, separations of typical kinds of neutral or charged homologs, such as alkylbenzenes, phenols (including isomeric compounds of hydroquinone, resorcin, and catechol), and anilines (including isomeric compounds of o-phenylenediamine and 1,4-phenylenediamine), were performed, respectively on the prepared column under the mode of pressurized pCEC. Effects of the buffer pH and the mobile phase composition on the linear velocity of mobile phase and the retention factors of these compounds were investigated. It was found that the retention mechanism of charged solutes could be attributed to a mixed mode of hydrophobic interaction and electrophoresis, while an RP chromatographic behavior on the monolithic stationary phases was exhibited for neutral solutes. Especially, basic compounds such as anilines were well separated on the monolithic columns in the "counterdirectional mode," which effectively eliminated the electrostatic adsorption of basic analytes on the charged surface of the stationary phases. 相似文献
955.
Magnetic diphase nanostructures of ZnFe2O4/γ-Fe2O3 were synthesized by a solvothermal method. The formation reactions were optimized by tuning the initial molar ratios of Fe/Zn. All samples were characterized by X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, and Raman spectra. It is found that when the initial molar ratio of Fe/Zn is larger than 2, a diphase magnetic nanostructure of ZnFe2O4/γ-Fe2O3 was formed, in which the presence of ZnFe2O4 enhanced the thermal stability of γ-Fe2O3. Further increasing the initial molar ratio of Fe/Zn larger than 6 destabilized the diphase nanostructure and yielded traces of secondary phase α-Fe2O3. The grain surfaces of diphase nanostructure exhibited a spin-glass-like structure. At room temperature, all diphase nanostructures are superparamagnetic with saturation magnetization being increased with γ-Fe2O3 content. 相似文献
956.
Large-eddy-simulation of 3-dimensional Rayleigh-Taylor instability in incompressible fluids 总被引:1,自引:0,他引:1
The 3-dimensional incompressible Rayleigh-Taylor instability is numerically studied through the large-eddy-simulation ( LES)
approach based on the passive scalar transport model. Both the instantaneous velocity and the passive scalar fields excited
by sinusoidal perturbation and random perturbation are simulated. A full treatment of the whole evolution process of the instability
is addressed. To verify the reliability of the LES code, the averaged turbulent energy as well as the flux of passive scalar
are calculated at both the resolved scale and the subgrid scale. Our results show good agreement with the experimental and
other numerical work. The LES method has proved to be an effective approach to the Rayleigh-Taylor instability. 相似文献
957.
Jingjing Yang Lei Li Prof. Chong Xiao Prof. Yi Xie 《Angewandte Chemie (International ed. in English)》2023,62(47):e202311911
Photocatalysis, particularly plasmon-mediated photocatalysis, offers a green and sustainable approach for direct nitrogen oxidation into nitrate under ambient conditions. However, the unsatisfactory photocatalytic efficiency caused by the limited localized electromagnetic field enhancement and short hot carrier lifetime of traditional plasmonic catalysts is a stumbling block to the large-scale application of plasmon photocatalytic technology. Herein, we design and demonstrate the dual-plasmonic heterojunction (Bi/CsxWO3) achieves efficient and selective photocatalytic N2 oxidation. The yield of NO3− over Bi/CsxWO3 (694.32 μg g−1 h−1) are 2.4 times that over CsxWO3 (292.12 μg g−1 h−1) under full-spectrum irradiation. The surface dual-plasmon resonance coupling effect generates a surge of localized electromagnetic field intensity to boost the formation efficiency and delay the self-thermalization of energetic hot carriers. Ultimately, electrons participate in the formation of ⋅O2−, while holes involve in the generation of ⋅OH and the activation of N2. The synergistic effect of multiple reactive oxygen species drives the direct photosynthesis of NO3−, which achieves the overall-utilization of photoexcited electrons and holes in photocatalytic reaction. The concept that the dual-plasmon resonance coupling effect facilitates the directional overall-utilization of photoexcited carriers will pave a new way for the rational design of efficient photocatalytic systems. 相似文献
958.
具有聚集诱导发光效应的咔唑基三苯乙烯衍生物单体及聚合物 总被引:1,自引:0,他引:1
合成了一类新的咔唑基三苯乙烯衍生物单体及其聚合物.利用示差扫描量热法(DSC)、热重分析法(TGA)、紫外可见分光光度法和荧光分光光度法等对单体和聚合物的性能进行了初步的表征.实验结果表明,该单体和聚合物具有较高的玻璃化转变温度(Tg),分别为210℃和229℃;单体和聚合物均具有很高的热稳定性,热失重5%的温度分别为466℃和467℃;单体具有明显的聚集诱导发光性能(AIE),而聚合物则具有聚集诱导增强发光性能(AIEE);所合成的单体和聚合物有望在OLED器件以及化学传感器上得到应用. 相似文献
959.
本工作用包括热晕、湍流和风等效应的等压近似下四维激光传输程序,数值计算了激光大气传输中的整束热畸变效应及其理想相位补偿,得到了各种情况下的激光大气传输畸变图象,并分析了热晕和湍流的相互作用。另外,还讨论了时、空步长的选取原则。 相似文献
960.
介绍了函数的最大项展开式和CRM展开式及其图形表示,提出函数K图和dj图的零点的概念,并以此为基础讨论了基于零点的函数K图和dj图之间的转换方法。 相似文献