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31.
Annual concentrations of toxic air contaminants are of primary concern from the perspective of chronic human exposure assessment and risk analysis. Despite recent advances in air quality monitoring technology, resource and technical constraints often impose limitations on the availability of a sufficient number of ambient concentration measurements for performing environmental risk analysis. Therefore, sample size limitations, representativeness of data, and uncertainties in the estimated annual mean concentration must be examined before performing quantitative risk analysis. In this paper, we discuss several factors that need to be considered in designing field-sampling programs for toxic air contaminants and in verifying compliance with environmental regulations. Specifically, we examine the behavior of SO2, TSP, and CO data as surrogates for toxic air contaminants and as examples of point source, area source, and line source-dominated pollutants, respectively, from the standpoint of sampling design. We demonstrate the use of bootstrap resampling method and normal theory in estimating the annual mean concentration and its 95% confidence bounds from limited sampling data, and illustrate the application of operating characteristic (OC) curves to determine optimum sample size and other sampling strategies. We also outline a statistical procedure, based on a one-sided t-test, that utilizes the sampled concentration data for evaluating whether a sampling site is compliance with relevant ambient guideline concentrations for toxic air contaminants. 相似文献
32.
孟伟根 《绍兴文理学院学报》2003,23(2):52-54
随着科学技术的发展 ,研究和探讨科技翻译的著作不断问世 ,但是目前有些论述科技英汉、汉英翻译的书籍在使用汉语语法术语方面不够正确。该文从词、句子成分和句的角度分析了汉语语法术语误用的情况。 相似文献
33.
Mark Bebbington Chin-Diew Lai Riardas Zitikis 《Australian & New Zealand Journal of Statistics》2007,49(3):251-265
Finding optimal, or at least good, maintenance and repair policies is crucial in reliability engineering. Likewise, describing life phases of human mortality is important when determining social policy or insurance premiums. In these tasks, one searches for distributions to fit data and then makes inferences about the population(s). In the present paper, we focus on bathtub‐type distributions and provide a view of certain problems, methods and solutions, and a few challenges, that can be encountered in reliability engineering, survival analysis, demography and actuarial science. 相似文献
34.
Nicholas T. Longford 《Statistics and Computing》2003,13(1):67-80
The weaknesses of established model selection procedures based on hypothesis testing and similar criteria are discussed and an alternative based on synthetic (composite) estimation is proposed. It is developed for the problem of prediction in ordinary regression and its properties are explored by simulations for the simple regression. Extensions to a general setting are described and an example with multiple regression is analysed. Arguments are presented against using a selected model for any inferences. 相似文献
35.
It is often of interest to find the maximum or near maxima among a set of vector‐valued parameters in a statistical model; in the case of disease mapping, for example, these correspond to relative‐risk “hotspots” where public‐health intervention may be needed. The general problem is one of estimating nonlinear functions of the ensemble of relative risks, but biased estimates result if posterior means are simply substituted into these nonlinear functions. The authors obtain better estimates of extrema from a new, weighted ranks squared error loss function. The derivation of these Bayes estimators assumes a hidden‐Markov random‐field model for relative risks, and their behaviour is illustrated with real and simulated data. 相似文献
36.
王广德 《白城师范学院学报》2003,(4)
本文简述了空间概念的发展历程。经典力学和SR把空间看作虚无,而GR则认为空间是 物质的。从而指出了空间概念是人类思维的自由创造。 相似文献
37.
吴健 《扬州大学学报(人文社会科学版)》2003,7(4):9-13
突破前人在马克思主义理论发展中具有十分重要的意义,马克思主义的发展史实际上就是一部不断突破前人的历史。只有突破前人,马克思主义才能适应客观形势的发展变化,才能保持理论的科学性和正确性,才能指导新的实践。突破前人既是人类认识运动基本规律的生动体现,又是马克思主义发展的客观轨迹。突破前人是有规可循的。突破前人必须既要善于继承前人更要勇于超越前人。继承前人的前提是坚持马克思主义的基本原理,核心是坚持解放思想、实事求是、与时俱进,关键是分析理论自身的局限性;超越前人的前提是潜心研究新情况新问题,核心是充分尊重群众的首创精神,关键是发扬锲而不舍的理论创造精神。 相似文献
38.
徐兴祥 《吉林师范大学学报》2004,32(2):54-57
经济法是现代市场经济发展到一定阶段出现政府干预失灵的特定历史下产生的法律部门和法律学科.它不仅是政府干预经济的有效手段,也是政府干预的约束和规范,是政府干预法治化和市场秩序优化的必然需求.同时,现代经济法法益保护也具有双重性既侧重于社会公共利益的保护,又兼顾市场经济个体私利的保护,实现社会公益和个体私益的最大协调和平衡. 相似文献
39.
建构适合我国国情的新型医疗救助体制 总被引:5,自引:0,他引:5
吴任慰 《南京医科大学学报(社会科学版)》2004,4(3):202-205
医疗救助是社会救助体制的重要组成部分,它是政府和社会对贫困人口中因病而无经济能力进行治疗的人实施专项帮助和支持的行为。文章对我国实施医疗救助的迫切性与重要性加以论述,并提出建构适合我国国情的新型医疗救助体制的构想。 相似文献
40.
Jarrett J. Barber Alan E. Gelfand John A. Silander 《Revue canadienne de statistique》2006,34(4):659-676
The authors consider the issue of map positional error, or the difference between location as represented in a spatial database (i.e., a map) and the corresponding unobservable true location. They propose a fully model‐based approach that incorporates aspects of the map registration process commonly performed by users of geographic informations systems, including rubber‐sheeting. They explain how estimates of positional error can be obtained, hence estimates of true location. They show that with multiple maps of varying accuracy along with ground truthing data, suitable model averaging offers a strategy for using all of the maps to learn about true location. 相似文献