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981.
Tunçbilek Ekrem Arıcı Müslüm Bouadila Salwa Wonorahardjo Surjamanto 《Journal of Thermal Analysis and Calorimetry》2020,141(1):613-624
Journal of Thermal Analysis and Calorimetry - In this work, thermal performance of a conventional brick incorporating phase change material (PCM) is studied. The influence of brick containing PCM... 相似文献
982.
Polarization-dependent efficient Cherenkov radiation at visible wavelengths in hollow-core photonic crystal fiber cladding
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Efficient Cherenkov radiation (CR) is experimentally generated by a soliton self-frequency shift (SSFS) in a knot of hollow-core photonic crystal fiber (HC-PCF). When the angle of the half-wave plate is rotated from 0° to 45° , the Raman soliton shifts from 2227 to 2300 nm, the output power of the CR increases 8.15 times, and the maximum output power ratio of the CR at 556 nm to the residual pump is estimated to be 20:1. The width of the output optical spectrum at visible wavelengths broadens from 25 to 45 nm, and the conversion efficiency of the CR can be above 28%. Moreover, the influences of the pump polarization and wavelength on the CR are studied, and the corresponding nonlinear processes are discussed. 相似文献
983.
Soheila Sameni Catherine Jeunesse Dr. Dominique Matt Dr. Loïc Toupet Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(40):10446-10456
The first diphosphines based on a double calixarene, namely 1,4 (or 1,3)‐bis‐(5‐diphenylphosphino‐25,26,27,28‐tetrapropoxycalix[4]aren‐17‐yl)benzene ( L2 , L3 ) were each prepared in four steps starting from 5,17‐dibromo‐25,26,27,28‐tetrapropoxycalix[4]arene. Upon reaction of L2 with [Au(tht)(thf)]BF4, (tht=C4H8S) a rigid metallo‐capsule was quantitatively formed, which adopts an oblique form owing to the distinct nature of the spacers linking the two calixarene half‐spheres. In the solid state, the 1,4‐substituted phenylene linker is turned towards the gold ion, suggesting the existence of weak bonding interactions between two aromatic CH protons of this ring and the metal centre (Au???H=2.67 Å). In contrast to this gold complex, the related silver complex shows dynamic behaviour in solution, the exchange between two enantiomeric oblique forms being facilitated by the greater stereochemical flexibility of AgI vs. AuI. A heteronuclear 109Ag{1H} HMQC experiment established strong correlations between the CH protons of the phenylene linker and the 109Ag ion. Dynamic behaviour similar to that observed for the silver complex was further observed in trans‐[PtCl2? L2 ], a chelate complex that could be obtained quantitatively from L2 and [PtCl2(PhCN)2]. The intended formation of a chelate complex leading to a capsule with an endo‐oriented metal centre was achieved by reacting L3 with [Pd(allyl)(thf)2]BF4. The complex thus formed constitutes the first organometallic transition metal complex embedded in a cavity with large portals. Binding of [RuCl2(p‐cymene)] to L2 and L3 resulted in self‐compacting bimetallic complexes in which each calixarene basket entraps a Ru(p‐cymene) unit, thereby forming molecules occupying a minimal volume. 相似文献
984.
Two homochiral metallosalen complexes, Ni(salen) (salen = (1R,2R)-(-)-diaminocyclohexane-N,N'-bis(3-tert-butyl-5-(4'-benzoic acid)-salicylidene) 1 and Cu(salen) 2, have been synthesized and characterized by IR, microanalysis, TGA, powder and single-crystal X-ray crystallography. Both 1 and 2 crystallize in orthorhombic space group P21212 with Z = 4. For 1, a = 12.082(2), b = 15.447(3), c = 18.784(4) , V = 3505.7(12) 3, Mr = 731.50, Dc = 1.386 g/cm3, μ = 0.606 mm–1, F(000) = 1544, the final GOOF = 1.043, R = 0.0496 and wR = 0.1248 for 4791 observed reflections with I > 2σ(I). For 2, a = 12.181(2), b = 15.501(3), c = 18.877(4) , V = 3564.3(12) 3, Mr = 736.33, Dc = 1.372 g/cm3, μ = 0.665 mm–1, F(000) = 1548, the final GOOF = 1.062, R = 0.0575 and wR = 0.1508 for 4562 observed reflections with I > 2σ(I). The crystal structures of 1 and 2 are isostructural with very similar supramolecular structures. An infinite two-dimensional network is generated by hydrogen bonding interactions and intermolecular π···π interactions. 相似文献
985.
Fluoropolymer blends have been widely used as binders for exterior coatings because of their excellent resistance to ultra-violet (UV) radiation as well as to many corrosive chemical agents.It is known that the fluorinated component usually has a lower glass transition temperature and easily crystallizes in the final structure depending upon the blend composition and sample annealing condition.We investigated the effect of blend composition and annealing process (slow and fast cooling) on the surface mor... 相似文献
986.
Two new C-glucoside oxanthrones,6-methoxyl-10-hydroxyaloin A(1) and 6-methoxyl-10-hydroxyaloin B(2),were isolated from the roots of Rumex gmelini Turcz.Their structures were elucidated on the basis of spectroscopic techniques and chemical means. 相似文献
987.
Turan Kaya Yazıcılar Evrim Yılmaz Gürkan İbrahim Uçar Canan Kazak 《Transition Metal Chemistry》2009,34(6):669-676
Four novel transition metal benzenesulfonate (BS) complexes of imidazole (im) with a general formula [M(imH)3(H2O)3]·(BS)2 [M=Mn(II) (1), Ni(II) (2), Co(II) (3)] and [Cu(BS)(imH)3]·(BS) (4) have been synthesized and characterized by physicochemical and spectroscopic methods. The complexes 2 and 3 have also been characterized by single X-ray diffraction technique. The BS anion in complexes 1–3 acts as a counter anion, while in complex 4, it acts as both ligand and counter anion. The Ni and Co complexes are isomorphous, crystallizing in the monoclinic crystal
system with C2/c space group. Each metal(II) atom in 2 and 3 is octahedrally coordinated by three imidazole and three aqua ligands, adopting a mer-coordination mode with Ni(II) or Co(II) centers. In both 2 and 3, the H2C atom has bifurcated donor (O3 and O5) atoms, forming a bifurcated hydrogen bond. This hydrogen bond links the complex
cation and BS anion, forming one-dimensional hydrogen-bonded supramolecular chains. The complexes exhibit different decomposition
characteristics. Magnetic susceptibility measurement shows that complex 3 has orbital interactions. 相似文献
988.
989.
Analysis of stability and error estimates for three methods approximating a nonlinear reaction-diffusion equation
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Costic u a Moro c sanu Silviu Pav u al C u at u alin Trenchea 《Journal of Applied Analysis & Computation》2017,7(1):1-19
We present the error analysis of three time-stepping schemes used in the discretization of a nonlinear reaction-diffusion equation with Neumann boundary conditions, relevant in phase transition. We prove $L^\infty$ stability by maximum principle arguments, and derive error estimates using energy methods for the implicit Euler, and two implicit-explicit approaches, a linearized scheme and a fractional step method. A numerical experiment validates the theoretical results, comparing the accuracy of the methods. 相似文献
990.
Ruud Peters Ingrid Elbers Anna Undas Eelco Sijtsma Sophie Briffa Pauline Carnell-Morris Agnieszka Siupa Tae-Hyun Yoon Loïc Burr David Schmid Jutta Tentschert Yves Hachenberger Harald Jungnickel Andreas Luch Florian Meier Jovana Kocic Jaeseok Kim Byong Chon Park Barry Hardy Colin Johnston Kerstin Jurkschat Jrg Radnik Vasile-Dan Hodoroaba Iseult Lynch Eugenia Valsami-Jones 《Molecules (Basel, Switzerland)》2021,26(17)
ACEnano is an EU-funded project which aims at developing, optimising and validating methods for the detection and characterisation of nanomaterials (NMs) in increasingly complex matrices to improve confidence in the results and support their use in regulation. Within this project, several interlaboratory comparisons (ILCs) for the determination of particle size and concentration have been organised to benchmark existing analytical methods. In this paper the results of a number of these ILCs for the characterisation of NMs are presented and discussed. The results of the analyses of pristine well-defined particles such as 60 nm Au NMs in a simple aqueous suspension showed that laboratories are well capable of determining the sizes of these particles. The analysis of particles in complex matrices or formulations such as consumer products resulted in larger variations in particle sizes within technologies and clear differences in capability between techniques. Sunscreen lotion sample analysis by laboratories using spICP-MS and TEM/SEM identified and confirmed the TiO2 particles as being nanoscale and compliant with the EU definition of an NM for regulatory purposes. In a toothpaste sample orthogonal results by PTA, spICP-MS and TEM/SEM agreed and stated the TiO2 particles as not fitting the EU definition of an NM. In general, from the results of these ILCs we conclude that laboratories are well capable of determining particle sizes of NM, even in fairly complex formulations. 相似文献