全文获取类型
收费全文 | 310篇 |
免费 | 35篇 |
国内免费 | 2篇 |
专业分类
化学 | 263篇 |
晶体学 | 2篇 |
力学 | 10篇 |
数学 | 33篇 |
物理学 | 39篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 10篇 |
2021年 | 20篇 |
2020年 | 11篇 |
2019年 | 15篇 |
2018年 | 15篇 |
2017年 | 4篇 |
2016年 | 27篇 |
2015年 | 17篇 |
2014年 | 14篇 |
2013年 | 31篇 |
2012年 | 22篇 |
2011年 | 35篇 |
2010年 | 15篇 |
2009年 | 8篇 |
2008年 | 23篇 |
2007年 | 12篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1997年 | 3篇 |
1995年 | 1篇 |
1987年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1926年 | 1篇 |
1896年 | 1篇 |
排序方式: 共有347条查询结果,搜索用时 31 毫秒
171.
Maxime Robin Valrie Pique Robert Faure Jean‐Pierre Galy 《Journal of heterocyclic chemistry》2002,39(5):1083-1085
The synthesis of N‐aryl anthranilic acid derivatives bearing dioxolo, dioxino, cyclopent, and imidazolo supplementary ring systems is reported. The Ullmann‐Goldberg condensation of the N‐aryl anthranilic acid is improved in yield and reaction time, compared to conventional heating; by ultrasonic irradiation. 相似文献
172.
Gibson KF Correia-Ledo D Couture M Graham D Masson JF 《Chemical communications (Cambridge, England)》2011,47(12):3404-3406
Mapping the transition of Ag nanotriangle to nanohole arrays revealed that the optimal SERS response was obtained near the transition. Correlated AFM and Raman imaging provided novel experimental proof that hot spots are located on Ag islands for nanotriangle arrays and in the core area of the hole for nanohole arrays, which is in agreement with previous theoretical predictions. 相似文献
173.
Durka M Buffet K Iehl J Holler M Nierengarten JF Taganna J Bouckaert J Vincent SP 《Chemical communications (Cambridge, England)》2011,47(4):1321-1323
Fullerene hexakis-adducts bearing 12 peripheral mannose moieties have been prepared by grafting sugar derivatives onto the fullerene core and assayed as inhibitors of FimH, a bacterial adhesin, using isothermal titration calorimetry, surface plasmon resonance and hemagglutination assays. 相似文献
174.
We provide in this article a new proof of the uniqueness of the flow solution to ordinary differential equations with BV vector fields that have divergence in L
∞ (or in L
1), when the flow is assumed nearly incompressible (see the text for the definition of this term). The novelty of the proof
lies in the fact it does not use the associated transport equation. 相似文献
175.
We consider sweeping a system through a Landau-Zener avoided crossing, when that system is also coupled to an environment or noise. Unsurprisingly, we find that decoherence suppresses the coherent oscillations of quantum superpositions of system states, as superpositions decohere into mixed states. However, we also find an effect we call "Lamb-assisted coherent oscillations," in which a Lamb shift exponentially enhances the coherent-oscillation amplitude. This dominates for high-frequency environments such as super-Ohmic environments, where the coherent oscillations can grow exponentially as either the environment coupling or temperature are increased. The effect could be used as an experimental probe for high-frequency environments in such systems as molecular magnets, solid-state qubits, spin-polarized gases (neutrons or He3), or Bose condensates. 相似文献
176.
177.
In this paper, we use rigorous numerics to compute several global smooth branches of steady states for a system of three reaction-diffusion PDEs introduced by Iida et al. [J. Math. Biol. 53(4):617–641, 2006] to study the effect of cross-diffusion in competitive interactions. An explicit and mathematically rigorous construction of a global bifurcation diagram is done, except in small neighborhoods of the bifurcations. The proposed method, even though influenced by the work of van den Berg et al. [Math. Comput. 79(271):1565–1584, 2010], introduces new analytic estimates, a new gluing-free approach for the construction of global smooth branches and provides a detailed analysis of the choice of the parameters to be made in order to maximize the chances of performing successfully the computational proofs. 相似文献
178.
Maxime Crochemore Lucian Ilie Costas S. Iliopoulos Marcin Kubica Wojciech Rytter Tomasz Waleń 《European Journal of Combinatorics》2013
The Longest Previous Factor array gives, for each position i in a string y, the length of the longest factor (substring) of y that occurs both at i and to the left of i in y. The Longest Previous Factor array is central in many text compression techniques as well as in the most efficient algorithms for detecting motifs and repetitions occurring in a text. Computing the Longest Previous Factor array requires usually the Suffix Array and the Longest Common Prefix array. We give the first time–space optimal algorithm that computes the Longest Previous Factor array, given the Suffix Array and the Longest Common Prefix array. We also give the first linear-time algorithm that computes the permutation that applied to the Longest Common Prefix array produces the Longest Previous Factor array. 相似文献
179.
Martin Depardieu Maxime Nollet Mathieu Destribats Véronique Schmitt Rénal Backov 《Particle & Particle Systems Characterization》2013,30(2):204-204
Complex wax@water@SiO2 multicore capsules are synthesized by combining sol‐gel process and formulation of wax‐in‐water‐in‐oil double emulsions. The inner direct wax‐in‐water emulsion is stabilized with modified silica nanoparticles using limited coalescence occurring in Pickering emulsions. In a second step, this obtained liquid dispersion is emulsified in poly‐dimethylsiloxane (PDMS) using a non ionic surfactant to stabilize the second water/oil interface. Finally, a sol‐gel process is employed to mineralize the as‐generated double emulsions giving rise to wax@water@SiO2 multicore capsules. Due to the wax volume expansion through melting, the as‐synthesized multicore capsules offer thermally stimulated release that is enhanced when surfactant is added in the surrounding continuous oil phase. In addition, the melted wax release can be tuned from a one‐step process to a more sequential dropping mode by varying the mineral precursor tetraethoxy‐orthosilane (TEOS) concentration in the oily phase during mineralization. 相似文献
180.
Armando Castillo Paulina Ceballos Pilar Santos Margarita Cern Perumal Venkatesan Enrique Prez-Gutirrez Martha Sosa-Rivadeneyra Subbiah Thamotharan Maxime A. Siegler María Judith Percino 《Molecules (Basel, Switzerland)》2021,26(6)
The compounds I (Z)-2-(phenyl)-3-(2,4,5-trimethoxyphenyl)acrylonitrile with one side (2,4,5-MeO-), one symmetrical (2Z,2′Z)-2,2′-(1,4-phenylene)bis(3-(2,4,5-trimethoxyphenyl)acrylonitrile), II (both sides with (2,4,5-MeO-), and three positional isomers with pyridine (Z)-2-(pyridin-2- 3, or 4-yl)-3-(2,4,5-trimethoxyphenyl)acrylonitrile, III–V were synthetized and characterized by UV-Vis, fluorescence, IR, H1-NMR, and EI mass spectrometry as well as single crystal X-ray diffraction (SCXRD). The optical properties were strongly influenced by the solvent (hyperchromic and hypochromic shift), which were compared with the solid state. According to the solvatochromism theory, the excited-state (μe) and ground-state (μg) dipole moments were calculated based on the variation of Stokes shift with the solvent’s relative permittivity, refractive index, and polarity parameters. SCXRD analyses revealed that the compounds I and II crystallized in the monoclinic system with the space group, P21/n and P21/c, respectively, and with Z = 4 and 2. III, IV, and V crystallized in space groups: orthorhombic, Pbca; triclinic, P-1; and monoclinic, P21 with Z = 1, 2, and 2, respectively. The intermolecular interactions for compounds I–V were investigated using the CCDC Mercury software and their energies were quantified using PIXEL. The density of states (DOS), molecular electrostatic potential surfaces (MEPS), and natural bond orbitals (NBO) of the compounds were determined to evaluate the photophysical properties. 相似文献