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101.
The Monte Carlo computer simulation technique of classical statistical mechanics is employed to determine the structure and thermodynamics of binary microclusters of Lennard-Jones atoms as a function of cluster size, composition and temperature. Further, amorphous microclusters are prepared by a Monte Carlo quench, and their structural properties are examined. The properties of interest include the internal energy, instantaneous “snapshot” pictures of the microcluster's atomic configuration, and the single-particle and pair distribution functions. The Lennard-Jones potential parameters are chosen to model Ar13, Ar7Kr6, Ar36Kr19 and Ar19Kr36, as well as to crudely model the bimetallic clusters of Cu19Ni36, Cu19Ru36 and Cu19Os36. A large variety of interesting features associated with these systems are described. 相似文献
102.
D. B. Abraham 《Communications in Mathematical Physics》1978,60(2):181-191
A representation of the pair correlation function for the rectangular Ising model in zero magnetic field is derived using a new spinor technique; this enables the scaling limit to be established, as well as several analytical properties of the scaling functions.Supported by the Fonds National Suisse de la Recherche Scientifique, by the National Science Foundation Grant No. PHY76-17191, and by the National Research Council of Canada Grant No. NRC A9344 相似文献
103.
104.
Abraham Boyarsky 《Advances in Applied Mathematics》1985,6(1):113-128
Let {τr} be the family of maps from [0,1] into [0,1] with properties similar to those of τr(x) = rx(1 ? x), 0 ≤ r ≤ 4. The limiting behaviour of orbits {τrj(x)}j∞ = 1 is a complicated and discontinuous function of the parameter r. The stochastic approximation to the difference equation xn + 1 = τr(xn), xn + 1 = τr(xn) + W, where W is a fixed random variable independent of r and xn, is considered. It is shown that this Markov process admits a unique absolutely continuous invariant measure μr and, furthermore, that the map r → μr is continuous. Such a result is important in applications, since slight changes in the shape of τr no longer cause discontinuous consequences in the limiting behaviour of the system. 相似文献
105.
Tamam L Kraack H Sloutskin E Ocko BM Pershan PS Ulman A Deutsch M 《The journal of physical chemistry. B》2005,109(25):12534-12543
The molecular-scale structure and phase behavior of single-component Langmuir films of 4'-methyl-4-mercaptobiphenyl (MMB) and 4'-perfluoromethyl-4-mercaptobiphenyl (FMMB) on mercury were studied using surface tensiometry, grazing incidence X-ray diffraction, and X-ray reflectivity. At low coverages, a condensed but in-plane disordered single layer of surface-parallel molecules is found for both compounds. At high coverages, both compounds exhibit in-plane-ordered phases of standing-up molecules. For MMB, the biphenyl core dominates the structure, yielding a centered-rectangular unit cell with an area A(x) of 21.8 A(2)/molecule, with molecules tilted by approximately 14 degrees from the surface normal in the nearest-neighbor direction, and a coherence length xi of >1000 A for the crystalline domains. For FMMB, the perfluoromethyl group dominates the structure, yielding a hexagonal unit cell with untilted molecules, an area A(x) of 24.2 A(2)/molecule, and a much smaller xi of approximately 110 A. The structure is discussed in comparison with self-assembled monolayers of MMB on crystalline Au(111) and similar-length alkanethiolate SAMs on Au(111) and on mercury. The differences in the structure are discussed and traced to the differences in the substrate's surface structure, and in the molecular cross section and rigidity. 相似文献
106.
We consider a tier of weakened bonds along the center line of a two-dimensional Ising ferromagnet strip as a model of a grain boundary. When an interface traverses such a strip at an angle, whether or not there is a continuous pinning-depinning transition at subcritical temperature depends on this angle and the degree of bond weakening. We also study the relaxation of such a system to its equilibrium state using continuous time Monte Carlo simulation with Kawasaki dynamics; this reveals a matter transport mechanism confined to the grain boundary. 相似文献
107.
108.
Photo-lithographically impregnated and molecularly imprinted polymer thin film for biosensor applications 总被引:1,自引:0,他引:1
A voltammetric sensor for albuterol was investigated where we combined the techniques of microfabrication and molecular imprinting to construct on-chip devices using photoirradiation of cross-linkable polymers. Molecularly imprinted polymer was coated as a thin film onto the gold working electrode on chip and the analyte was directly quantified by differential pulse voltammetric measurements. 相似文献
109.
Krishnamohan Sharma CV Chusuei CC Clérac R Möller T Dunbar KR Clearfield A 《Inorganic chemistry》2003,42(25):8300-8308
Phosphoric acid forms two distinct coordination compounds with manganese salts in aqueous media, a two-dimensional layered structure, [Mn(HPO4).(H2O)3], 1, under ambient conditions, and a three-dimensional synthetic mineral, [Mn5(mu-OH2)2(HPO4)2(PO4)2(H2O)2], 2, under hydrothermal procedures, at 120 degrees C. In compound 1, the oxygen atom of the doubly deprotonated phosphoric acid interconnects the metal centers to form a layered structure. The neutral hydrophilic layers of 1 are separated by 5.5 A and may potentially intercalate hydrophilic organic guest molecules. The metal centers in 2 are octahedral and bridged by PO4(3-), HPO4(2-), and OH2 groups to form a complex three-dimensional network. XPS analysis on 1 and 2 confirms that manganese exists in the +2 oxidation state. Compound 2 is a poor ion exchanger, but some improvement is observed on partial dehydration. The magnetic properties of both 1 and 2 were studied in detail to examine the amplitude of the magnetic interactions through phosphate ligand bridges. While 1 reveals dominant antiferromagnetic interactions between the spin carriers, a complete investigation of the magnetic properties of 2 revealed its true nature to be a glassy magnet. 相似文献
110.
Shafi KV Ulman A Lai J Yang NL Cui MH 《Journal of the American Chemical Society》2003,125(14):4010-4011
We present a new route for the preparation of gamma-alumina and YAG nanoparticles. Metal salts of ethylhexanoic acids provide good solubility in hydrocarbon solvents and allow efficient ultrasonication. The sonication product is an alumioxane gel, which can reversibly collapse and reform, depending on the solvent used. The dried gel nanoparticles are calcined at temperatures significantly lower than those used in conventional syntheses, resulting in gamma-alumina nanoparticles. This is due to the complete mixing of elements at the atomic level and the small size of the formed nanoparticles. 相似文献