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151.
The paradigm of extended enterprise is the core competency focused.An extended enterprise expands its scope from bounding a single enterprise to including additional processes performed by other enterprises.The integration of processes is enterprise based.This paper proposes a recursive enterprises interconnected chain model for the extended enterprise,and presents an enterprisebased integration framework for the extended enterprise .The case study is based on a motorcycle group coporation. 相似文献
152.
We describe the development and successful implementation of a decision support system now being used by several leading firms
in the architecture and space planning industries. The system, which we call SPDS (spatial programming design system) has
the following characteristics: (i) user-friendly convenience features permitting architects and space planners to operate
the system without being experienced programmers; (ii) interactive capabilities allowing the user to control and to manipulate
relevant parameters, orchestrating conditions to which his or her intuition provides valuable input; (iii) informative and
understandable graphics, providing visual displays of interconnections that the computer itself treats in a more abstract
methematical form; (iv) convenient ways to change configurations, and to carry out ‘what if’ analyses calling on the system’s
decision support capabilities; (v) a collection of new methods, invisible to the user, capable of generating good solutions
to the mathematical programming problems that underlie each major design component. These new methods succeed in generating
high quality solutions to a collection of complex discrete, highly nonlinear problems. While these problems could only be
solved in hours, or not at all, with previously existing software, the new methods obtain answers in seconds to minutes on
a minicomputer. Major users, including Dalton, Dalton, Newport, and Marshal Erdwin, report numerous advantages of the system
over traditional architectural design methods. 相似文献
153.
The reference shrinkage curve of clay soil 总被引:1,自引:0,他引:1
The objective of this work is to develop and validate a model that predicts the reference soil shrinkage curve, that is one without crack volume contribution, as a necessary preliminary step in future estimation of soil crack volume from soil shrinkage data. Current soil shrinkage models are based on the approximation of soil shrinkage data by some a priori taken mathematical expressions and justified by the fitting of their parameters to the data. However, the crack volume entering the data is not single valued and depends on shrinkage conditions. Unlike that the reference shrinkage curve is single valued. For soils with sufficiently high clay content when there are no large pores (lacunar pores) inside the intra-aggregate clay, the reference shrinkage curve is derived from the assumption of the rigid superficial (interface) layer of aggregates with changed pore-size range and distribution compared with the intra-aggregate matrix. This consideration is based on accounting for contributions of the interface aggregate layer and intra-aggregate matrix to the soil volume and water content during shrinkage. The reference shrinkage curve is predicted by eight fundamental physical immediately measured parameters of (i) the intra-aggregate matrix (including clay content); (ii) the aggregate structure; and (iii) the mean silt-sand grain size or mean interface layer thickness. The model was validated using the data for eight soils. In addition to the major potential application for estimating a soil crack volume, the model explains differences between the observed shrinkage curves of soil and pure clay, and it can have other numerous applications. 相似文献
154.
A fluid flow and heat transfer model has been developed for the reactive, porous bed of the biomass gasifier to simulate pressure drop, temperature profile in the bed and flow rates. The conservation equations, momentum equation and energy equation are used to describe fluid and heat transport in porous gasifier bed. The model accounted for drag at wall, and the effect of radial as well as axial variation in bed porosity to predict pressure drop in bed. Heat transfer has been modeled using effective thermal conductivity approach. Model predictions are validated against the experiments, while effective thermal conductivity values are tested qualitatively using models available in literature. Parametric analysis has been carried out to investigate the effect of various parameters on bed temperature profile and pressure drop through the gasifier. The temperature profile is found to be very sensitive to gas flow rate, and heat generation in oxidation zone, while high bed temperature, gas flow rate and the reduction in feedstock particle size are found to cause a marked increase in pressure drop through the gasifier. The temperatures of the down stream zones are more sensitive to any change in heat generation in the bed as compared to upstream zone. Author recommends that the size of preheating zone may be extended up to pyrolysis zone in order to enhance preheating of input air, while thermal insulation should not be less than 15 cm. 相似文献
155.
Modeling the dynamic behavior of shape memory alloys 总被引:4,自引:0,他引:4
Stefan Seelecke 《International Journal of Non》2002,37(8):837-1374
The paper studies the single degree of freedom vibration of a rigid mass suspended by a thin-walled shape memory alloy tube under torsional loading. The behavior is analyzed for the cases of quasiplasticity (low temperatures) and pseudoelasticity (high temperatures) on the basis of an improved version of the Müller–Achenbach model. To illustrate the strong hysteresis-induced damping capacity and the non-linear vibration characteristics, both, free and forced vibrations are considered in the first part of the paper. This is done on the basis of an isothermal version of the model, while the second part of the paper focuses on the effect of non-constant temperature caused by the rate-dependent release and absorption of latent heats. 相似文献
156.
Cell cycle regulates proliferative cell capacity under normal or pathologic conditions, and in general it governs all in vivo/in vitro cell growth and proliferation processes. Mathematical simulation by means of reliable and predictive models represents an important tool to interpret experiment results, to facilitate the definition of the optimal operating conditions for in vitro cultivation, or to predict the effect of a specific drug in normal/pathologic mammalian cells. Along these lines, a novel model of cell cycle progression is proposed in this work. Specifically, it is based on a population balance (PB) approach that allows one to quantitatively describe cell cycle progression through the different phases experienced by each cell of the entire population during its own life. The transition between two consecutive cell cycle phases is simulated by taking advantage of the biochemical kinetic model developed by Gérard and Goldbeter (2009) which involves cyclin-dependent kinases (CDKs) whose regulation is achieved through a variety of mechanisms that include association with cyclins and protein inhibitors, phosphorylation–dephosphorylation, and cyclin synthesis or degradation. This biochemical model properly describes the entire cell cycle of mammalian cells by maintaining a sufficient level of detail useful to identify check point for transition and to estimate phase duration required by PB. Specific examples are discussed to illustrate the ability of the proposed model to simulate the effect of drugs for in vitro trials of interest in oncology, regenerative medicine and tissue engineering. 相似文献
157.
Classroom teachers need a well‐developed deep understanding of fractions and pedagogic practices so they can provide meaningful experiences for students to explore and construct ideas about fractions. This study sought to examine prospective elementary teachers' understandings of fraction by focusing specifically on their use of fractions meanings and interpretations. Results indicated that prospective elementary teachers bring with them to their final methods course a limited understanding of fractions and that experiences in methods courses resulted only in minor improvement of those limited understandings. The limited part‐whole understanding of fractions that prospective elementary teachers entered the course with was resilient. The implications of this study suggest a need for prospective elementary teachers to continue to develop their conceptual understanding of fractions and for changes to the content and instructional strategies of mathematics content courses designed for prospective elementary teachers. 相似文献
158.
The self-consistent model of heat and mass transfer during convective drying of capillary porous media describing both the
first and the second periods of drying is presented in Musielak (Wydawnictwo Politechniki Poznańskiej, seria Rozprawy, nr
386 (2004a); Chem. Process Eng. 25, 393–409 (2004b)). The results of simulations of processes in steady conditions are shown (Musielak Wydawnictwo Politechniki
Poznańskiej, seria Rozprawy, nr 386 (2004a); Chem. Process Eng. 25, 393–409 (2004b)). The main aim of the present work is to compare experimental results with those from numerical simulations.
Three convective drying processes have been performed experimentally. The first and the second periods of drying are considered,
during which the humidity of air in the dryer changes due to evaporation. The first process is used to establish drying parameters,
whereafter the two remaining processes are simulated. Good agreement between experimental and simulation results is found,
both qualitative and quantitative. 相似文献
159.
A reduction of friction by vibrations has been observed in various experiments. This effect can be applied to actively control
frictional forces by modulating vibrations. Moreover, common methods of controlling friction rely on lubricants and suitable
material combinations. The superimposition of vibrations can further reduce the friction force. This study presents a theoretical
approach based on the Dahl friction model that describes the friction reduction observed in the presence of the tangential
vibrations at an arbitrary angle. Analysis results indicated that the tangential compliance should be considered in modeling
the effect of vibrations in reducing friction. At any vibration angle, the tangential compliance of the contacts reduces the
friction reduction effect. The vibrations parallel to the macroscopic velocity are most effective for friction reduction. 相似文献
160.