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941.
942.
943.
944.
An efficient strategy enabling the construction of polysubstituted 1,2-dihydroquinoline derivatives mediated by the commercially available, economical, and environmentally benign iodine (3 mol %) under mild conditions was developed. Various arylamines and α-ketoesters could participate in this cascade reaction, and the desired products were obtained in excellent yields up to 98%. 相似文献
945.
One new sesquiterpene lactone,1 α,8 α,9 α-trihydroxyeudesman-3(4),7(11)-dien-8 β,12-olide(1) and two new phenylpropanoidsubstituted catechin glycosides,glabraoside C(2) and glabraoside D(3) were isolated from the whole plant of Sarcandra glabra. Their structures were established by the analyses of spectral and chemical evidences. 相似文献
946.
The PdCl2-catalyzed allylation of heteroarenes is presented. Various heteroarenes including O-, N-, and S-based ones were allylated efficiently with a rich range of allylic acetates in the presence of only 2 mol % of PdCl2, without the need of bases/acids, additives, and external supporting ligands. In addition, the reactions were carried out under mild and simple conditions just by stirring the two reactants and catalyst in CH2Cl2 at 60 °C. Moreover, the by-product produced was non-toxic acetic acid. Thus, the method presented in this work provides a general, clean, and operationally simple approach for the functionalization of heteroarenes. Finally, a preliminary mechanistic study suggested that the Pd(II) may be reduced in situ by the heteroarenes to Pd(0), which serves as the active metal center to catalyze the following allylations of heteroarenes via a Tsuji–Trost pathway. 相似文献
947.
Polymerizable Molecular Silsesquioxane Cage Armored Hybrid Microcapsules with In Situ Shell Functionalization 下载免费PDF全文
Dr. Yuxiu Xing Dr. Jun Peng Prof. Kai Xu Dr. Weihong Lin Dr. Shuxi Gao Yuanyuan Ren Xuefeng Gui Shengyuan Liang Prof. Mingcai Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):2114-2126
We prepared core–shell polymer–silsesquioxane hybrid microcapsules from cage‐like methacryloxypropyl silsesquioxanes (CMSQs) and styrene (St). The presence of CMSQ can moderately reduce the interfacial tension between St and water and help to emulsify the monomer prior to polymerization. Dynamic light scattering (DLS) and TEM analysis demonstrated that uniform core–shell latex particles were achieved. The polymer latex particles were subsequently transformed into well‐defined hollow nanospheres by removing the polystyrene (PS) core with 1:1 ethanol/cyclohexane. High‐resolution TEM and nitrogen adsorption–desorption analysis showed that the final nanospheres possessed hollow cavities and had porous shells; the pore size was approximately 2–3 nm. The nanospheres exhibited large surface areas (up to 486 m2 g?1) and preferential adsorption, and they demonstrated the highest reported methylene blue adsorption capacity (95.1 mg g?1). Moreover, the uniform distribution of the methacryloyl moiety on the hollow nanospheres endowed them with more potential properties. These results could provide a new benchmark for preparing hollow microspheres by a facile one‐step template‐free method for various applications. 相似文献
948.
Nonlinear Dynamics - This paper investigates the parameter and state estimation problems for a class of fractional-order nonlinear systems subject to the perturbation on the observer gain. The... 相似文献
949.
Kinetics and Mechanism of the Reaction of a Ruthenium(VI) Nitrido Complex with HSO3− and SO32− in Aqueous Solution 下载免费PDF全文
Dr. Qian Wang Hong Yan Zhao Dr. Wai‐Lun Man Dr. William W. Y. Lam Dr. Kai‐Chung Lau Prof. Tai‐Chu Lau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(31):10754-10758
The kinetics and mechanism of the reaction of SIV (SO32?+HSO3?) with a ruthenium(VI) nitrido complex, [(L)RuVI(N)(OH2)]+ (RuVIN, L=N,N′‐bis(salicylidene)‐o‐cyclohexyldiamine dianion), in aqueous acidic solutions are reported. The kinetic results are consistent with parallel pathways involving oxidation of HSO3? and SO32? by RuVIN. A deuterium isotope effect of 4.7 is observed in the HSO3? pathway. Based on experimental results and DFT calculations the proposed mechanism involves concerted N?S bond formation (partial N‐atom transfer) between RuVIN and HSO3? and H+ transfer from HSO3? to a H2O molecule. 相似文献
950.
Zhonggang Zhang Danting Yue Changrong He Shuang Ye Weiguo Wang Jinliang Yuan 《Heat and Mass Transfer》2014,50(11):1575-1586
In this study, a three-dimensional computational fluid dynamics model has been developed for an anode-supported planar SOFC. The conservation equations of mass, momentum, species/charges and thermal energy are solved by finite volume method for a complete unit cell consisting of 13 parallel channels in both anode and cathode. The simulation results of the developed model are well in agreement with the experimental data obtained at same conditions. In this study, the co-flow arrangement with hydrogen utilization of 60 % and operating voltage of 0.7 V is used as the base case, and compared with the counter-flow arrangement. The predicted results reveals that the maximum temperature obtained in the counter-flow arrangement is about 10 °C lower than that of co-flow, but the counter-flow arrangement has a higher temperature gradient between the respective anodes and cathodes in a cross-section normal to the main flow direction, especially in the air inlet region of the cell (x = 0.04 m),which is very harmful to the lifetime of materials. The current density is very unevenly distributed along and normal to the flow direction for both the co- and counter-flow arrangements, and the maximum values occur at junctions of the electrodes, channels and ribs, which causes higher over-potentials and ohmic heating. 相似文献