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51.
52.
LYCOS: the Lyngby Co-Synthesis System   总被引:5,自引:0,他引:5  
This paper describes the LYCOS system, an experimental co-synthesis environment. We present the motivation and philosophy of LYCOS and after an overview of the entire system, the individual parts are described. We use a single CPU, single ASIC target architecture and we describe the techniques we use to estimate metrics concerning hardware, software and communication in this architecture. Finally we present a novel partitioning technique called PACE, which has shown to produce excellent results, and we demonstrate how partitioning is used to do design space exploration.  相似文献   
53.
We present a new algorithm for nonlinear minimax optimization which is well suited for large and sparse problems. The method is based on trust regions and sequential linear programming. On each iteration a linear minimax problem is solved for a basic step. If necessary, this is followed by the determination of a minimum norm corrective step based on a first-order Taylor approximation. No Hessian information needs to be stored. Global convergence is proved. This new method has been extensively tested and compared with other methods, including two well known codes for nonlinear programming. The numerical tests indicate that in many cases the new method can find the solution in just as few iterations as methods based on approximate second-order information. The tests also show that for some problems the corrective steps give much faster convergence than for similar methods which do not employ such steps.Research supported partly by The Nordic Council of Ministers, The Icelandic Science Council, The University of Iceland Research Fund and The Danish Science Research Council.  相似文献   
54.
We report on the determination of the mineralogy of the atmospherically suspended Martian dust particles using backscattering 57Fe Mössbauer spectroscopy on dust accumulated onto the magnets onboard the Mars Exploration Rovers. The spectra can be interpreted in terms of minerals of igneous origin, and shows only limited, if any, amounts of secondary minerals that may have formed in the presence of liquid water. These findings suggest that the dust has formed in a dry environment over long time in the history of the planet.  相似文献   
55.
The magnetic properties of synthetic goethite, precipitated from a SiO2-containing Fe(III) solution, have been studied. The Mössbauer spectra show the coexistence of a quadrupole doublet and a magnetically split component in a large temperature range. The area ratio of these two components depends strongly on temperature, indicating a normal superparamagnetic behaviour of isolated crystallites. This is in contrast to the behaviour normally exhibited by pure samples of microcrystalline goethite, in which strong magnetic interactions among the crystallites lead to a superferromagnetic behaviour. The results show that the magnetic interactions among the crystallites are drastically diminished when amorphous SiO2 separates the goethite crystallites.  相似文献   
56.
This paper presents a new spectral model for solving the fully nonlinear potential flow problem for water waves in a single horizontal dimension. At the heart of the numerical method is the solution to the Laplace equation which is solved using a variant of the σ ‐transform. The method discretizes the spatial part of the governing equations using the Galerkin method and the temporal part using the classical fourth‐order Runge‐Kutta method. A careful investigation of the numerical method's stability properties is carried out, and it is shown that the method is stable up to a certain threshold steepness when applied to nonlinear monochromatic waves in deep water. Above this threshold artificial damping may be employed to obtain stable solutions. The accuracy of the model is tested for: (i) highly nonlinear progressive wave trains, (ii) solitary wave reflection, and (iii) deep water wave focusing events. In all cases it is demonstrated that the model is capable of obtaining excellent results, essentially up to very near breaking.  相似文献   
57.
The time-dependent Ginzburg-Landau equation is solved numerically for type-II superconductors of complex geometry using the finite element method. The geometry has a marked influence on the magnetic vortex distribution and the vortex dynamics. We have observed generation of giant vortices at boundary defects, suppressing the superconducting state far into the superconductor.  相似文献   
58.
Thin hydrogel films based on an ABA triblock copolymer gelator [where A is pH-sensitive poly(2-(diisopropylamino)ethyl methacrylate) (PDPA) and B is biocompatible poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC)] were used as a stimulus-responsive substrate that allows fine adjustment of the mechanical environment experienced by mouse myoblast cells. The hydrogel film elasticity could be reversibly modulated by a factor of 40 via careful pH adjustment without adversely affecting cell viability. Myoblast cells exhibited pronounced stress fiber formation and flattening on increasing the hydrogel elasticity. As a new tool to evaluate the strength of cell adhesion, we combined a picosecond laser with an inverted microscope and utilized the strong shock wave created by the laser pulse to determine the critical pressure required for cell detachment. Furthermore, we demonstrate that an abrupt jump in the hydrogel elasticity can be utilized to monitor how cells adapt their morphology to changes in their mechanical environment.  相似文献   
59.
Realization of the cloud computing infrastructure requires access to data anywhere, anytime at any device at a sufficient perceived quality of service. Many Western European countries, such as Denmark, have a high percentage of individuals (inhabitants and companies) that has access to broadband internet via cable, satellite and mobile. This gives a unique position in roll-out and deploying intelligent cloud based services that can be applied for a number of purposes, but where lack of sufficient capacity/quality and IT readiness will be barriers in realization of the “Global Information Multimedia Communication Village (GIMCV)”. Broadband is here defined as more than 2 Mbps. In this paper, the combination of e-commerce, cloud computing and broadband infrastructure has our focus, and its unique possibilities for the overall IT society. However, it is also about a significant number of Small and Medium sized Enterprises (SMEs) that today applies manual billing systems or Excel like systems in combination with severe lacks of sufficient IT skills. This means that the most commonly used systems are the ones requiring the most of our time. Therefore, the move for the SME towards e-commerce and electronic processes has a significant economical potential for the SMEs. E-commerce and other internet based services will simplify their business, and hence allow the SMEs to focus on their core business which was their raison d’être. In addition to this can be added other fundamental IT systems that will help their business, but that is outside the scope of this paper. Furthermore, this paper focuses on infrastructural barriers and cloud computing; not only focusing on bandwidth, but also the entire issue of service offering. Services offered via cloud computing solutions will minimize the SMEs investment in own hardware (HW), software (SW) and maintenance. The focus is also the upgrade to a superior infrastructure that provides the platform for efficient cloud computing, for e-commerce, and beyond.  相似文献   
60.
X-ray diffraction data of high quality measured to high resolution on crystals of the two pentitol epimers ribitol (centric) and xylitol (acentric) at 101, 141, and 181 K and data on the two compounds previously recorded at 122 K have formed the basis for multipole refinements with the VALRAY system. Our analysis showed that it is possible to obtain a reliable crystal electron density for an acentric compound (xylitol) from X-ray diffraction data and that the thermal motion can be deconvoluted from the static density in this temperature range. The Bader-type topological analysis of the static electron densities revealed virtually identical intramolecular interactions as well as very similar hydrogen bond interactions of ribitol and xylitol; the only minor differences are found in the weaker intermolecular interactions. The high-level periodic DFT calculations are in accordance with the thermodynamic measurements that show that the two pentitols have identical sublimation energies. A rigid body normal coordinate analysis was performed on the atomic displacement parameters obtained at the four different temperatures. The translational and librational mean square deviations derived through this analysis were used in a quantum statistical approach to derive frequencies of the corresponding harmonic oscillators. The analysis showed a consistent vibrational model for all temperatures. The frequencies were subsequently used to calculate crystal entropies assuming an Einstein-type behavior. These calculations show that the crystal entropy of ribitol is 8 J K(-1) mol(-1) higher than the crystal entropy of xylitol, confirming that it is a difference in the entropy of the two compounds that causes the difference in their free energy. Our results presented in this Article show the potential to use X-ray diffraction data to obtain physicochemical properties of crystals.  相似文献   
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