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111.
Marchenko E. S. Yasenchuk Yu. F. Gunther S. V. Baigonakova G. A. Kokorev O. V. Shishelova A. A. Fatyushina O. A. 《Russian Physics Journal》2020,62(10):1789-1793
Russian Physics Journal - A gradient magnetron-sputtered three-layer laminated Ti–Ni–Ti coating is formed by the method of reaction synthesis on a titanium nickelide substrate. The... 相似文献
112.
Sarah E. Border Radoslav Z. Pavlović Dr. Lei Zhiquan Michael J. Gunther Han Wang Prof. Honggang Cui Prof. Jovica D. Badjić 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(1):273-279
Discovering novel and functional photoresponsive materials is of interest for improving controlled release of molecules and scavenging toxic compounds for cleaning our environment or designing chemosensors. In this study, we report on the photoinduced decarboxylation of basket 1 6−, containing three glutamic acids at its rim. This concave compound is, in an aqueous environment (30 mm phosphate buffer at pH 7.0), monomeric (1H NMR DOSY, DLS) with glutamic acid residues randomly oriented about its rim (1H NMR and MM-OPLS3). The irradiation (300 nm) of 1 6− leads to the exclusive removal of its α-carboxylates to give amphiphilic 2 3− possessing γ-carboxylates. The photochemical transformation is a consecutive reaction with mono- and bis-decarboxylated products observed with 1H NMR spectroscopy and ESI mass spectrometry. Amphiphilic 2 3− is a preorganized molecule (MM-OPLS3) that, in water, aggregates into organic nanoparticles (ca. 50–200 nm in diameter; DLS, TEM and cryo-TEM) having a critical aggregation concentration of 12 μm (UV/Vis). As the transition of monomeric 1 6− into nanoparticulate 2 3− is triggered with light, we reasoned that stimuli-responsive formation of the soft material lends itself to nanotechnology applications such as controlled release or scavenging of targeted compounds. 相似文献
113.
114.
Yulia Krupskaya Alexey Alfonsov Anupama Parameswaran Vladislav Kataev Dr. Rüdiger Klingeler Dr. Gunther Steinfeld Norman Beyer Mathias Gressenbuch Berthold Kersting Prof. Dr. Bernd Büchner Prof. Dr. 《Chemphyschem》2010,11(9):1961-1970
The ability of bridging thiophenolate groups (RS?) to transmit magnetic exchange interactions between paramagnetic NiII ions is examined. Specific attention is paid to complexes with large Ni? SR? Ni angles. For this purpose, dinuclear [Ni2L1(μ‐OAc)?I2][I5] ( 2 ) and trinuclear [Ni3L2(OAc)2][BPh4]2 ( 3 ), where H2L1 and H2L2 represent 24‐membered macrocyclic amino‐thiophenol ligands, are prepared and fully characterized by IR‐ and UV/Vis spectroscopy, X‐ray crystallography, static magnetization M measurements and high‐field electron spin resonance (HF‐ESR). The dinuclear complex 2 has a central N3Ni2(μ‐S)2(μ‐OAc)Ni2N3 core with a mean Ni? S? Ni angle of 92°. The macrocycle L2 supports a trinuclear complex 3 , with distorted octahedral N2O2S2 and N2O3S coordination environments for one central and two terminal NiII ions, respectively. The Ni? S? Ni angles are at 132.8° and 133.5°. We find that the variation of the bond angles has a very strong impact on the magnetic properties of the Ni complexes. In the case of the Ni2‐complex, temperature T and magnetic field B dependencies of M reveal a ferromagnetic coupling J=?29 cm?1 between two NiII ions (H=JS1S2). HF‐ESR measurements yield a negative axial magnetic anisotropy (D<0) which implies a bistable (easy axis) magnetic ground state. In contrast, for the Ni3‐complex we find an appreciable antiferromagnetic coupling J′=97 cm?1 between the NiII ions and a positive axial magnetic anisotropy (D>0) which implies an easy plane situation. 相似文献
115.
(146)Sm (T(1/2) = 10(8) y) is a long-lived radionuclide which has been produced in significant amounts during burning in a supernova (SN). Detection of this SN produced long-lived radionuclide on Earth may be helpful for getting information on nuclear synthesis at the time of our solar system's formation. Only accelerator mass spectrometry (AMS) can determine such minute traces of (146)Sm still expected in the Earth's crust. However, the villain of (146)Sm measurement through AMS is its naturally occurring stable isobar (146)Nd which is a million times more abundant than the trace amount of (146)Sm. Therefore an efficient method for the separation of samarium and neodymium is required to measure (146)Sm through AMS. A simple liquid-liquid extraction (LLX) based method for separation of samarium and neodymium has been developed using radiometric simulation. Di-(2-ethylhexyl)phosphoric acid (HDEHP) has been used as the organic reagent. A very high separation factor ( approximately 10(6)) can be achieved when a solution containing samarium and neodymium is reduced by hydroxylamine hydrochloride followed by extraction with 0.1% HDEHP diluted in cyclohexane from 0.025 M HCl solution. 相似文献
116.
We show that fixed energy scattering measurements for the magnetic Schrödinger operator uniquely determine the magnetic field and electric potential in dimensions n?3. The magnetic potential, its first derivatives, and the electric potential are assumed to be exponentially decaying. This improves an earlier result of Eskin and Ralston (1995) [5] which considered potentials with many derivatives. The proof is close to arguments in inverse boundary problems, and is based on constructing complex geometrical optics solutions to the Schrödinger equation via a pseudodifferential conjugation argument. 相似文献
117.
Switching on cell adhesion with microelectrodes 总被引:2,自引:0,他引:2
118.
Krebs T Tan HL Andersson G Morgner H Gregory Van Patten P 《Physical chemistry chemical physics : PCCP》2006,8(46):5462-5468
As-deposited films of multilayered polyelectrolytes are considered to be non-equilibrium structures. Due to the strong attraction between oppositely charged polyions, polyelectrolyte interdiffusion is thought to be suppressed during the adsorption process. Equilibration is promoted by a decrease of the electrostatic attraction between polyion pairs. We have used neutral impact collision ion scattering spectroscopy to investigate the influence of polyelectrolyte multilayer annealing in water and aqueous 1 M NaCl solutions at different temperatures (20 and 70 degrees C) on the increase in interpenetration of a single polyelectrolyte layer throughout the whole film. The multilayers were composed of poly(4-vinylpyridinium) and poly(4-styrenesulfonate). Contrast between neighboring layers was established by labelling the layer in question with the heavy atom ruthenium. It is found that both temperature and salt increase layer interpenetration, whereas salt has a stronger influence than temperature. From numerical simulations polyelectrolyte diffusion coefficients were evaluated for the different annealing conditions. The influence of temperature and salt on the equilibration of the film is interpreted in terms of increased screening of polyion charges and binding of small counterions to polyion monomeric units. 相似文献
119.
Journaux Y Glaser T Steinfeld G Lozan V Kersting B 《Dalton transactions (Cambridge, England : 2003)》2006,(14):1738-1748
The ligating properties of the 24-membered macrocyclic dinucleating hexaazadithiophenolate ligand (L(Me))2- towards the transition metal ions Cr(II), Mn(II), Fe(II), Co(II), Ni(II) and Zn(II) have been examined. It is demonstrated that this ligand forms an isostructural series of bioctahedral [(L(Me))M(II)2(OAc)]+ complexes with Mn(II) (2), Fe(II) (3), Co(II) (4), Ni(II) (5) and Zn(II) (6). The reaction of (L(Me))2- with two equivalents of CrCl2 and NaOAc followed by air-oxidation produced the complex [(L(Me))Cr(III)H2(OAc)]2+ (1), which is the first example for a mononuclear complex of (L(Me))2-. Complexes 2-6 contain a central N3M(II)(mu-SR)2(mu-OAc)M(II)N3 core with an exogenous acetate bridge. The Cr(III) ion in is bonded to three N and two S atoms of (L(Me))2- and an O atom of a monodentate acetate coligand. In 2-6 there is a consistent decrease in the deviations of the bond angles from the ideal octahedral values such that the coordination polyhedra in the dinickel complex 5 are more regular than in the dimanganese compound 2. The temperature dependent magnetic susceptibility measurements reveal the magnetic exchange interactions in the [(L(Me))M(II)2(OAc)]+ cations to be relatively weak. Intramolecular antiferromagnetic exchange interactions are present in the Mn(II)2, Fe(II)2 and Co(II)2 complexes where J = -5.1, -10.6 and approximately -2.0 cm(-1) (H = -2JS1S2). In contrast, in the dinickel complex 5 a ferromagnetic exchange interaction is present with J = +6.4 cm(-1). An explanation for this difference is qualitatively discussed in terms of the bonding differences. 相似文献
120.
The influence of moving boundaries on the stability of quantum Hamiltonian systems, in particular on the dynamics of quantum versions of the classical Pustilnikov model, is investigated (the latter consists of a masspoint bouncing above an oscillating plate under the influence of constant gravity.) It is shown that, in contrast to the classical Pustilnikov model, generic time-periodic boundary conditions (including the Dirichlet condition) on the quantum models do not allow unlimited energy gain (speeding up) of these systems. 相似文献