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991.
992.
指出城市道路交通拥堵的原因 .确立城市交通中诸关键因素之间相互关系的数学模型 相似文献
993.
In this paper, we derive an optimal ordering policy for an unreliable newsboy who can place two sequential orders before the start of a single selling season by using a demand forecast update. Supply yield is modeled using a uniform distribution considering both the minimum order guarantee and the maximum yield. Our results indicate that a firm should focus on increasing the minimum order guarantee from a first stage supplier to reduce its total supply chain cost. 相似文献
994.
M. Ali Khan 《Nonlinear Analysis: Theory, Methods & Applications》2011,74(1):171-181
In recent work, the authors set classical turnpike theory in the context of the economics of forestry, as developed by Mitra and Wan, and presented two far-reaching results. In this paper, we present a conceptual generalization that takes this theory and configures it around a set in the space of forest configurations rather than around the golden-rule forest configuration. Our set-valued analysis hinges on periodicity and yields the earlier results as corollaries under a non-interiority condition on the felicity function that shrinks the set to the point. The question that we pose, and answer, has obvious relevance to more general contexts and, in particular, to turnpike theory as developed by Samuelson, Gale, McKenzie, and their followers. 相似文献
995.
In a scale-free network,only a minority of nodes are connected very often,while the majority of nodes are connected rarely. However,what is the ratio of minority nodes to majority nodes resulting from the Matthew effect In this paper,based on a simple preferential random model,the poor-rich demarcation points are found to vary in a limited range,and form a poor-rich demarcation interval that approximates to k/m ∈ [3,4]. As a result,the (cumulative) degree distribution of a scale-free network can be divided into three intervals: the poor interval,the demarcation interval and the rich interval. The inequality of the degree distribution in each interval is measured. Finally,the Matthew effect is applied to the ABC analysis of project management. 相似文献
996.
O. Hellman 《Journal of Optimization Theory and Applications》1981,34(4):579-591
In Ref. 1, the author considered the following large-scale forest management problem. There is a system consisting of several factories which all use, as raw material, wood obtained from a large forest region. This forest is divided into a large number of subforests, each of which is felled after it has reached a given age, after which a new forest is immediately planted. The instants in time at which each subforest is felled are assumed to form a stationary point process. In Ref. 1, it was demonstrated how the parameters of the system must be chosen in order to achieve a flow of raw material such that the probability that a shortage will occur is less than a preset value. In the present paper, we consider the problem of maximizing the yield of a single subforest. 相似文献
997.
M. B. Gordon J. R. Iglesias V. Semeshenko J. P. Nadal 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,68(1):133-144
Crime is an economically relevant activity. It may represent a mechanism of wealth distribution but also a social and economic
burden because of the interference with regular legal activities and the cost of the law enforcement system. Sometimes it
may be less costly for the society to allow for some level of criminality. However, a drawback of such a policy is that it
may lead to a high increase of criminal activity, that may become hard to reduce later on. Here we investigate the level of
law enforcement required to keep crime within acceptable limits. A sharp phase transition is observed as a function of the
probability of punishment. We also analyze other consequences of criminality as the growth of the economy, the inequality
in the wealth distribution (the Gini coefficient) and other relevant quantities under different scenarios of criminal activity
and probabilities of apprehension. 相似文献
998.
J. B. Satinover D. Sornette 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,67(3):357-367
In the Minority, Majority and Dollar Games (MG, MAJG, $G) agents compete for rewards, acting in accord with the previously
best-performing of their strategies. Different aspects/kinds of real-world markets are modelled by these games. In the MG,
agents compete for scarce resources; in the MAJG agents imitate the group to exploit a trend; in the $G agents attempt to
predict and benefit both from trends and changes in the direction of a market. It has been previously shown that in the MG
for a reasonable number of preliminary time steps preceding equilibrium (Time Horizon MG, THMG), agents’ attempt to optimize
their gains by active strategy selection is “illusory”: the hypothetical gains of their strategies is greater on average than
agents’ actual average gains. Furthermore, if a small proportion of agents deliberately choose and act in accord with their
seemingly worst performing strategy, these outperform all other agents on average, and even attain mean positive gain, otherwise
rare for agents in the MG. This latter phenomenon raises the question as to how well the optimization procedure works in the
THMAJG and TH$G. We demonstrate that the illusion of control is absent in THMAJG and TH$G. This provides further clarification
of the kinds of situations subject to genuine control, and those not, in set-ups a priori defined to emphasize the importance
of optimization. 相似文献
999.
Industrial risks increate with technological progress. The study of potential risks is routine in the pharmaceutical–chemical industry. Here, like in other industrial activities, a risk coefficient is introduced that varies within space time limits.A control system of environmental safety and health monitoring processes should be based on the data obtained from Hazard and Operability Studies (HAZOP).The space variable influences the chemical risk coefficient that applies to the whole the production cycle (including waste recycling). For the sake of prevention, many enterprises have adopted the integrated management system, which is now moving to an additional required feature: environment and health protection and safety assurance inside and outside the industrial area (in compliance with UNI, ISO 14000 and OHSAS 18001standards).Our goal is to examine the technological–scientific–environmental changes in the pharmaceutical–chemical sector in order to asses the new extent of chemical regarding management systems.This will entail a cultural change that will call for the necessary economic strategies for industries to implement the appropriate environmental–technological programs. 相似文献
1000.
网上技术市场正逐步发展成为技术交易的主要形式.本文以中国浙江网上技术市场为例,从其定位和动力模式两方面探讨了网上技术市场的发展模式,以及从信息资源管理、技术交易管理和市场运作三方面探讨了网上技术市场的运行管理机制. 相似文献