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941.
Li Zhao Zhiwei Hu Chang‐Yang Kuo Tun‐Wen Pi Maw‐Kuen Wu Liu Hao Tjeng Alexander C. Komarek 《固体物理学:研究快报》2015,9(12):730-734
From magnetic susceptibility, dielectric permittivity, electric polarization and specific heat measurements we discover spin‐induced ferroelectricity and magnetoelectric coupling in Mn3TeO6 and observe two successive magnetic transitions at low temperatures. A non‐ferroelectric intermediate magnetic state occurs below 23 K and a multiferroic ground state emerges below 21 K. Moreover, Mn3TeO6 is a candidate for a multiferroic material where two types of incommensurate spin structures, cycloidal and helical, coexist. Theoretically, both spin substructures may contribute to the macro electric polarization via different mechanisms. This could open new ways of manipulating the ferroelectric polarization in a multiferroic material. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
942.
Alaa S. Abd-el-aziz Adam Piórko Andrzej S. Baranski Ronald G. Sutherland 《合成通讯》2013,43(11-12):1865-1870
Electrochemical reduction of the cyclopentadienyliron hexafluorophosphates of benzophenone, o-chlorophenyldibenzoylmethane and diethyl ethylphenylmalonate led to the liberation of arenes without reduction of keto or ester groups in over 85% yields. 相似文献
943.
Müge Sarı Yılmaz Sibel Kasap Sabriye Pişkin 《Journal of Thermal Analysis and Calorimetry》2013,112(3):1325-1333
Titanate nanotubes were synthesized utilizing the hydrothermal method using titanium dioxide nanoparticles. The experiments were carried out considering the process as a function of reaction temperature, time, NaOH concentration and the acidity of the washing solution. The formation of titanate nanotubes was shown to be affected strongly by variations in any parameter. The optimum conditions for the synthesis of titanate nanotubes were determined to be a reaction temperature of 190 °C, and a reaction time of 12 h, using 10 M NaOH concentration and the washing solution to have a pH of 5.5. In addition, thermogravimetric analysis (TG/DTG) was used to investigate the thermal behaviour and dehydration kinetics of titanate nanotubes. In order to better understand their thermal behaviour, the thermal analysis of bulk hydrogen trititanate was performed. The values of the apparent activation energies of the first and second dehydration stages for titanate nanotubes were 81.44 ± 15.85 and 82.69 ± 7.46 kJ mol?1, respectively. The values of the apparent activation energies of the first, second and third dehydration stages for bulk hydrogen trititanate were 115.93 ± 5.40, 137.58 ± 6.47 and 138.97 ± 8.47 kJ mol?1, respectively. 相似文献
944.
945.
Hassan N Ruso JM Piñeiro Á 《Langmuir : the ACS journal of surfaces and colloids》2011,27(16):9719-9728
The structure and physicochemical properties of the nanoparticles spontaneously formed within aqueous mixtures of the hydrogenated/fluorinated catanionic surfactant cetyltrimetylammonium perfluorooctanoate in the absence of counterions as a function of its concentration are investigated by a combined experimental/computational study at room temperature. Apparent molar volumes, isentropic apparent molar compressibilities, and dynamic light scattering measurements together with transmission and cryo-scanning electron as well as confocal laser microscopy images, and computational molecular dynamics simulations indicate that a variety of structures of different sizes coexist in solution with vesicles of ~160 nm diameter. Interestingly, the obtained nanostructures were observed to self-assemble from a random distribution of monomers in a time scale easily accessible by atomistic classical molecular dynamics simulations, allowing to provide a comprehensive structural and dynamic characterization of the surfactant molecules at atomic level within the different aggregates. Overall, it is demonstrated that the use of mixed fluorinated hydrogenated surfactant systems represents an easy strategy for the design of specific nanoscale structures. The detailed structural analysis provided in the present work is expected to be useful as a reference to guide the design of new nanoparticles based on different hydrogenated/fluorinated catanionic surfactants. 相似文献
946.
Santiago LE García C Lhiaubet-Vallet V Miranda MA Oyola R 《Photochemistry and photobiology》2011,87(3):611-617
2‐chlorothioxanthone (CTX) is used as photoinitiator for the reticulation of synthetic resins and for the preparation of pharmaceuticals. It was previously determined that CTX is the primary photoproduct of z‐chlorprothixene (CPTX) when irradiated at 313 nm and is formed in an autocatalyzed reaction through an energy‐transfer mechanism (Piñero et al. [2009] Photochem. Photobiol., 85 , 895–900). In this work, the photophysical properties of CTX were measured in acetonitrile/water solutions to determine if their magnitude can affect the side effects of CPTX. The results show that CTX has higher absorption coefficients in the visible region (400–420 nm) and higher triplet quantum yields than its parent compound. Similar to TX, both properties strongly depend on the solvent polarity/hydroxylicity. The quantum yield of the triplet intermediate is very close to the value of the phenothiazine triplets. The phenothiazines are the most phototoxic antidepressants. Therefore, given the appropriate microenvironment, the photosensitization side effects of CPTX can be intensified on the production of CTX. 相似文献
947.
Guo Yong Zhang Peng Xiang Zhang Hai Rong Zheng Xiang Yu Zhang Dang Li Gao Hui Zhang Li Pi Wing Kee Lee 《Optics & Laser Technology》2008,40(6):844-849
We have posed the design of a time-integral type laser energy meter based on anisotropic Seebeck effect for the first time. Anisotropic Seebeck effect is responsible for the laser-induced thermoelectric voltage effect in high temperature superconductor (HTSC) cuprates and colossal magnetoresistance (CMR) manganites thin films grown on tilted single crystal substrates. In this study, for an example, an epitaxial La2/3Ca1/3MnO3 thin film prepared on a tilted LaAlO3 substrate by standard pulsed-laser deposition (PLD) method is tested with a 1064-nm Q-switched Nd:YAG laser and its 2nd (532 nm), 3rd (355 nm), and 4th (266 nm) harmonics from room temperature to 16 K. The integral of the voltage signal with time shows a good linear relation with the laser energy per pulse in the measured wavelength and temperature range, which confirms the theoretical analysis given in this letter and can be used to design a time-integral type laser energy meter. The sensitivity increases as the film thickness increases or as the thermal diffusion constant decreases, which makes the time-integral type laser energy meter low cost as compared with the peak-voltage type. It operates with fast (nanosecond range) and broad-spectrum (from infrared to ultraviolet) response in wide temperature range (from room temperature to 10s K), and can be useful replacements for pyroelectric power/energy meters. 相似文献
948.
讨论了通有反向电流的两平行圆柱形导体交叠区域内的磁场分布,发现当电流密度大小相等时交叠区域内是一个均匀磁场. 相似文献
949.
A series of Al 2p, K 2p, O 1s and N 1s core‐level spectra have been used to characterize the interaction between potassium (K) and tris(8‐hydroxyquinoline) aluminium (Alq3) molecules in the K‐doped Alq3 layer. All core‐level spectra were tuned to be very surface sensitive in selecting various photon energies provided by the wide‐range beamline at the National Synchrotron Radiation Research Center, Taiwan. A critical K concentration (x = 2.4) exists in the K‐doped Alq3 layer, below which the K‐doped atoms generate a strained environment near the O and N atoms within 8‐quinolinoline ligands. This creates new O 1s and N 1s components on the lower binding‐energy side. Above the critical K coverage, the K‐doped atoms attach the O atoms in the Al—O—C bonds next to the phenoxide ring and replace Al—O—C bonds by forming K—O—C bonds. An Alq3 molecule is disassembled into Alq2 and Kq by bond cutting and bond formation. The Alq2 molecule can be further dissociated into Alq, or even Al, through subsequent formations of Kq. 相似文献
950.