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101.
The introduction of Co, Al, and Ti into LiMn2O4 cathode powders has been studied in this work. The substitution of 25% Mn with either of these metals is expected to improve the cycle ability of the cathode, while the Jahn–Teller effect is suppressed. The solid-state reaction method is used in order to produce the cathode materials, which are prepared at 750 or 800 °C. The materials are characterized by X-ray data and, electrochemically, by galvanostatic cycling at the 4-V range. Their capacity fading behavior is evaluated, and a further investigation into cycling at a higher voltage range is also presented. 相似文献
102.
Two make-to-order firms, each modelled as a single-server queue, compete for a common stream of (potential) customers by setting their service capacities (rates) and service prices. Each customer maximizes her expected return by getting service from a firm or by balking. We completely characterize the Nash equilibrium of the competition. 相似文献
103.
WU Ze-qing PANG Jin-qiao HAN Guo-xing 《原子与分子物理学报》2004,21(Z1):48-50
A model is developed to calculate emission spectrum of non-local thermodynamic equilibrium(NLTE) plasmas. The Collisional-Radiative model is adopted for non-LTE population calculations. Configuration-averaged rate coefficients that needed in the rate equations are obtained based on the first order perturbation theory. The Hatree-Fock-Slater self-consistent-field method is used to calculate electron wave functions. The present model is applied to the calculation of emissivity from a Ar plasma. The features of the spectra are in good agreement with those calculated by other theoretical models, but the data of the integrated emissivity differ by a factor 2~8. 相似文献
104.
This paper first reviews the history of the temperature dependence of reaction rate in reaction kinetics. The various equations which are in use today for expressing this dependence were delineated by van't Hoff almost one hundred years ago. Since an exponential form best describes this dependence for most thermal analysis reactions and, due to the fact that the simple Arrhenius equation (with a temperature-independent preexponential factor) has traditionally been used for this purpose, the mathematically intractable temperature integral often has become a necessary evil in the analysis of thermal analysis kinetics. Methods which avoid the temperature integral in kinetics analysis are discussed. The merits of various evaluations and approximations for the temperature integral are described and assessed in this paper. 相似文献
105.
S.-M. Kwon H.-S. Choi K.-Y. Lee 《Archive of Applied Mechanics (Ingenieur Archiv)》2002,72(2-3):160-170
Summary The steady-state of a propagation eccentric crack in a piezoelectric ceramic strip bonded between two elastic materials under
combined anti-plane mechanical shear and in-plane electrical loadings is considered in this paper. The analysis based on the
integral transform approach is conducted on the permeable crack condition. Field intensity factors and energy release rate
are obtained in terms of a Fredholm integral equation of the second kind. It is shown for this geometry that the crack propagation
speed has influence on the dynamic energy release rate. The initial crack branching angle for a PZT-5H piezoceramic structure
is predicted by the maximum energy release rate criterion.
Received 23 January 2001; accepted for publication 18 October 2001 相似文献
106.
To date, the lithium ion battery has become the focus of secondary battery studies. A considerable capacity loss during the first lithiation of its carbon electrode is a severe drawback of this kind of battery. It has been suggested frequently that the capacity loss was caused by the decomposition of the electrolyte on the surface of the carbon electrode. However, the contribution of binder reduction to this capacity loss has never been considered until now. This paper deals with the binder polytetrafluorethylene (PTFE) reduction and finds that it plays an important part in the capacity loss. It is found that (1) the capacity loss increased with increasing PTFE binder content, (2) the X-ray diffraction peaks corresponding to the PTFE, binder became weaker, while more of the lithium was consumed by the carbon electrode, and disappeared when the consumed amount of lithium exceeded the theoretical value of 1070 mAh per gram of PTFE and (3) the height of the high voltage plateau of the electrochemical titration curves was just a function of storage time, and the length of the plateau was a function of the PTFE content. 相似文献
107.
Y. Wu 《Annals of the Institute of Statistical Mathematics》1993,45(4):615-620
In this paper, upper bounds on the probabilities of wrong determination of the rank of covariance matrix of random effects in one-way random effects models are given, based on the information theoretic criterion. Under weak conditions, the bounds are shown of exponential-type.The work was partially supported by Natural Sciences and Engineering Research Council of Canada and Faculty Research Grant, Faculty of Arts, York University. 相似文献
108.
利用IOS近似模型,计算了星际分子云条件下E型CH3CN-H2含超精细能级的的碰撞跃迁速率系数。其温度范围是20K-140K。为研究分子云与恒星形成区的物理、化学性质提供了大量有用的基础分子数据。 相似文献
109.
This paper investigates the important infrastructure design and expansion problem for broadband wireless access networks subject to user demand constraints and system capacity constraints. For the problem, an integer program is derived and a heuristic solution procedure is proposed based on Lagrangean relaxation. In the computational experiments, our Lagrangean relaxation based algorithm can solve this complex design and expansion problem quickly and near optimally. Based on the test results, it is suggested that the proposed algorithm may be practically used for the infrastructure design and expansion problem for broadband wireless access networks. 相似文献
110.
We study a practice whereby a downstream firm makes to his supplier a premium-payment for a certain quantity of products. We show that the adoption of this practice can induce the supplier to build bigger capacity. The higher capacity level enables the supplier to satisfy a larger portion of demands from the downstream firm, and this leads to higher payoffs for both parties in the supply chain. With the assistance of an under-capacity penalty imposed on the supplier, this premium-payment scheme can help lure the parties into taking the channel-optimal actions. Our numerical examples help reveal various features of the scheme. 相似文献