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The asymptotic behavior of expectations of some exponential functionals of a Lévy process is studied. The key point is the observation that the asymptotics only depend on the sample paths with slowly decreasing local infimum. We give not only the convergence rate but also the expression of the limiting coefficient. The latter is given in terms of some transformations of the Lévy process based on its renewal function. As an application, we give an exact evaluation of the decay rate of the survival probability of a continuous-state branching process in random environment with stable branching mechanism. 相似文献
164.
The emergence of dynamic geometry environments challenges researchers in mathematics education to develop theories that capture learner’s growth in geometric understanding in this particular environment. This study coordinated the Pirie-Kieren theory and instrumental genesis to examine learner’s growth in geometric understanding when solving problems in a dynamic geometry environment. Data analysis suggested that coordinating the two theoretical approaches provided a productive means to capture the dynamic interaction between the growth in mathematical understanding and the formation/application of utilization scheme during a learner’s mathematical exploration with dynamic geometry software. The analysis of one episode on inscribing a square in a triangle was shared to illustrate this approach. This study contributes to the continuing conversation of “networking theories” in the mathematics education research community. By networking the two theoretical approaches, this paper presents a model for studying learner's growth in mathematical understanding in a dynamic learning environment while accounting for interaction with digital tools. 相似文献
165.
Let be a supercritical branching process in an independent and identically distributed random environment. We prove Cramér moderate deviations and Berry-Esseen bounds for log( ) uniformly in ,which extend the corresponding results by I. Grama, Q. Liu, and M. Miqueu [Stochastic Process. Appl., 2017, 127: 1255–1281] established for . The extension is interesting in theory, and is motivated by applications. A new method is developed for the proofs; some conditions of Grama et al. are relaxed in our present setting. An example of application is given in constructing confidence intervals to estimate the criticality parameter in terms of log( ) and n. 相似文献
166.
将改进的投入产出局部闭模型和分析方法应用到建筑节能研究领域.结合数量经济方法,建立了建筑节能经济-环境影响测算投入产出模型,应用该模型测算了2002年不同比例的既有建筑实施50%的建筑节能标准后的直接经济影响,然后测算通过各个产业部门之间的相互影响和相互作用后,建筑节能对国民经济其他产业部门的关联影响、对本部门的完全影响和对以GDP衡量的整个国民经济系统的影响.最后测算不同比例的既有建筑实施50%的建筑节能标准后减少的二氧化碳和二氧化硫的排放量. 相似文献
167.
中国经济增长与环境污染的协整关系研究——基于1991-2007年省际面板数据 总被引:3,自引:0,他引:3
利用1991-2007中国29个省市的面板数据,对经济增长与环境污染的长期均衡关系进行了研究,对人均实际GDP及代表环境污染的五类污染物排放指标进行了面板单位根检验和面板协整分析。结果表明,在五类污染物排放指标中,只有工业固体废弃物排放量与人均GDP之间符合EKC特征,工业废水排放量随经济增长而逐渐减少,而工业废气排放量与经济增长不存在协整关系。 相似文献
168.
本文是对"城市地质环境与工程"学术研讨会中关于城市工程地质评价专题的一个综述,主要包括城市基础地质填图与工程地质评价、城市工程地质环境地质信息技术两项内容。本文除对此部分论文作以概要介绍外,重点对工程地质评价的有关问题作以阐述。同时对相关问题的前景进行了探讨。 相似文献
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Abstract The study is focused on the dolomite-limestone drinking water aquifers in the Bo? massif, as well as on the andesite-aquifer containing mineral water in the vicinity of Roga?ka Slatina. The catchment area is limited and both drinking and mineral waters are discharged from the same source. The increasing use of deeper aquifers means that natural springs and shallow wells have become sporadic. Consequently new techniques of investigating recharge and aquifer capacity are required which can augment classical hydrogeological methods. Current research into the mineral and drinking water aquifers in the area of Roga?ka Slatina is based on measuring the isotopic composition of light elements, (H, C and O) as natural tracers. It can be concluded that all the groundwaters investigated are typically infiltrated meteoric water. The drinking waters are generally young and were infiltrated up to about ten years ago. The isotopic composition of oxygen is similar to recent precipitation (δ18O = -9.3 ± 1‰) and the drinking waters contain tritium. It was found that exploited mineral waters recharged aquifers during colder periods; they are only partly mixed with younger water as can be seen from the isotopic composition of oxygen and corrected 14C dating, which puts the mean ages at between around 100 and 8,000 years. With regard to the “nuclear period” (1960-64) with abnormally high tritium activities of precipitation, all the waters examined can be divided into at least three main infiltration groups depending on their measured tritium content: around 35 years old (> 80 T.U.), older (> 10 T.U.) and younger (10 to 60 T.U.). Detailed dating is possible following the above classification. Isotope exchange between rocks and water is negligible and therefore very deep circulation at the temperature conditions above 80°C does not occur. Dissolved inorganic carbon (DIC) in the drinking waters is the result of equilibrium reactions between carbonates and organically produced CO2 (δ13C = - 14.5 ± ‰), while the high concentrations of DIC (δ13C = + 3 ±‰) and CO2 observed in the mineral waters are generated by low-temperature decarbonatization processes and indicate the deep origin of CO2, from where gas migrates into mineral water aquifers. Correlation analyses between the parameters studied are performed. Useful conclusions concerning water circulation and the capacities of aquifer reservoirs are described which support the future optimal pumping of mineral and drinking water at the limited catchment area of Roga?ka Slatina and Bo?. 相似文献