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991.
992.
Hosseini M Ganjali MR Tavakoli M Norouzi P Faridbod F Goldooz H Badiei A 《Journal of fluorescence》2011,21(4):1509-1513
A novel and simple fluorescence enhancement method for selective pyrophosphate(PPi) sensing was proposed based on a 1:1 metal
complex formation between bis(8-hydroxy quinoline-5-solphonat) chloride aluminum(III) (Al(QS)2Cl), (L) and PPi in aqueous solution. The linear response range covers a concentration range of 1.6 × 10−7 to 1.0 × 10−5 mol/L of PPi and the detection limit of 2.3 × 10−8 mol/L. The association constant of L-PPi complex was calculated 2.6 × 105 L/mol. L was found to show selectively and sensitively fluorescence enhancement toward PPi over than I3-, NO3-, CN−, CO32−, Br−, Cl−, F−, H2PO4− and SO42−, which was attributed to higher stability of inorganic complex between pyrophosphate and L. 相似文献
993.
Joan A. Vaccaro 《Foundations of Physics》2011,41(10):1569-1596
An increasing number of experiments at the Belle, BNL, CERN, DAΦNE and SLAC accelerators are confirming the violation of time
reversal invariance (T). The violation signifies a fundamental asymmetry between the past and future and calls for a major
shift in the way we think about time. Here we show that processes which violate T symmetry induce destructive interference
between different paths that the universe can take through time. The interference eliminates all paths except for two that
represent continuously forwards and continuously backwards time evolution. Evidence from the accelerator experiments indicates
which path the universe is effectively following. This work may provide fresh insight into the long-standing problem of modeling
the dynamics of T violation processes. It suggests that T violation has previously unknown, large-scale physical effects and
that these effects underlie the origin of the unidirectionality of time. It may have implications for the Wheeler-DeWitt equation
of canonical quantum gravity. Finally it provides a view of the quantum nature of time itself. 相似文献
994.
Magdalena Ulmeanu Iuliana Iordache Mihaela Filipescu Valentin Craciun Simona Cinta Pinzaru Andreas Hörner 《Central European Journal of Physics》2011,9(5):1280-1287
Experimental studies on patterning hexagonal Ge nanostructures have been conducted on Si substrates through deposition of
Ge with colloidal particles as a mask. The deposited Ge thin film possesses, according to the X-ray diffraction measurements,
in plane texture, being epitaxial and aligned with the (111) Si substrate. The size distribution of the patterned Ge nanostructures
is narrow, as indicated by the atomic force microscopy and scanning electron microscopy measurements. We have obtained Ge
nanostructures with lateral dimension of 490 nm (height 12 nm), 200 nm (height 6 nm) and 82 nm (height 6 nm) by using different
sizes of polystyrene spheres. We have performed in depth studies of the Ge nanostructures’ behavior due to thermal and rapid
thermal post-annealing processes. FT micro-Raman spectroscopy shows that there is no Si intermixing during the annealing process.
In order to quantify the changes in the height and lateral dimension, we have performed atomic force microscopy and white
light interferometry analysis. The changes in shape and the decrease in the area of a cross-section of Ge nanostructure will
be discussed in respect to similar results shown in the literature for Ge thin films during the annealing process. 相似文献
995.
Olga Riba Robert J. Barnes Thomas B. Scott Murray N. Gardner Simon A. Jackman Ian P. Thompson 《Journal of nanoparticle research》2011,13(10):4591-4601
A reactivity study was undertaken to compare and assess the rate of dechlorination of chlorinated aliphatic hydrocarbons (CAHs)
by annealed and non-annealed nanoscale iron particles. The current study aims to resolve the uncertainties in recently published
work studying the effect of the annealing process on the reduction capability of nanoscale Fe particles. Comparison of the
normalized rate constants (m2/h/L) obtained for dechlorination reactions of trichloroethene (TCE) and cis-1,2-dichloroethene (cis-1,2-DCE) indicated that
annealing nanoscale Fe particles increases their reactivity ~30-fold. An electron transfer reaction mechanism for both types
of nanoscale particles was found to be responsible for CAH dechlorination, rather than a reduction reaction by activated H2 on the particle surface (i.e., hydrogenation, hydrogenolysis). Surface analysis of the particulate material using X-ray diffraction
(XRD) and transmission electron microscopy (TEM) together with surface area measurement by Brunauer, Emmett, Teller (BET)
indicate that the vacuum annealing process decreases the surface area and increases crystallinity. BET surface area analysis
recorded a decrease in nanoscale Fe particle surface area from 19.0 to 4.8 m2/g and crystallite dimensions inside the particle increased from 8.7 to 18.2 nm as a result of annealing. 相似文献
996.
The influence of interfacial barrier engineering on the resistance switching of In<sub>2</sub>O<sub>3</sub>:SnO<sub>2</sub>/TiO<sub>2</sub>/In<sub>2</sub>O<sub>3</sub>:SnO<sub>2</sub> device 下载免费PDF全文
The I–V characteristics of In2O3:SnO2/TiO2/In2O3:SnO2 junctions with different interfacial barriers are inves- tigated by comparing experiments. A two-step resistance switching process is found for samples with two interfacial barriers produced by specific thermal treatment on the interfaces. The nonsynchronous occurrence of conducting filament formation through the oxide bulk and the reduction in the interfacial barrier due to the migration of oxygen vacancies under the electric field is supposed to explain the two-step resistive switching process. The unique switching properties of the device, based on interfacial barrier engineering, could be exploited for novel applications in nonvolatile memory devices. 相似文献
997.
Hongzhi Luo Guodong Liu Fanbin Meng Jianqiang Li Enke Liu Guangheng Wu 《Journal of magnetism and magnetic materials》2012
The electronic structure and magnetic properties of new Fe-based Heusler alloys Fe2TiZ (Z = Ga, Ge, As, In, Sn and Sb) have been studied by first-principles calculations. In these alloys, the 24-electron Fe2TiGe, Fe2TiSn are nonmagnetic semiconductors and other compounds are all ferrimagnetic metals. Fe2TiAs and Fe2TiSb are predicted to be half-metals with 100% spin polarization. The spin polarization ratio in Fe2TiGa and Fe2TiIn is also quite high. The calculated total moment for Fe2TiAs and Fe2TiSb is 1 μB, which is mainly determined by the Fe partial moment. The half-metallicity of Fe2TiSb is stable under lattice distortion. The spin polarization of Fe2TiSb is found to be 100% for the lattice variation in a range of 5.6–6.1 Å, which is attractive in practical applications. 相似文献
998.
The effect of a thermal annealing treatment on the performance of bulk heterojunction photovoltaic cells based on poly[2-methoxy-5-(2′-ethyl-hexyloxy)-p-phenylene vinylene] (MEH-PPV) and fullerene (C60) composites is investigated. Upon thermal annealing at 120 °C, short-circuit current and power conversion efficiency (η) are more than tripled, while a sharp rise by eight times in and η is found for the device annealed at 200 °C. It is concluded that the improved phase separation between MEH-PPV and C60 leads to the enhancement of and η at 120 °C, while thermodynamic molecule arrangement at the higher temperature of ∼200 °C induces a significant increase in all photovoltaic parameters of composite devices except the open-circuit voltage . 相似文献
999.
Classic molecular dynamics (MD) calculations were performed to investigate the deposition of thin hydrocarbon film. SiC (1 0 0) surfaces were bombarded with energetic CH3 molecules at impact energies ranging from 50 to 150 eV. The simulated results show that the deposition yield of H atoms decreases with increasing incident energy, which is in good agreement with experiments. During the initial stages, with breaking Si-C bonds in SiC by CH3 impacting, H atoms preferentially reacts with resulting Si to form Si-H bond. The C/H ratio in the grown films increases with increasing incident energy. In the grown films, CH species are dominant. For 50 eV, H-Csp3 bond is dominant. With increasing energy to 200 eV, the atomic density of H-Csp2 bond increases. 相似文献
1000.