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1.
We describe a risk-based analytical framework for estimating traffic fatalities that combines the probability of a crash and the probability of fatality in the event of a crash. As an illustrative application, we use the methodology to explore the role of vehicle mix and vehicle prevalence on long-run fatality trends for a range of transportation growth scenarios that may be relevant to developing societies. We assume crash rates between different road users are proportional to their roadway use and estimate case fatality ratios (CFRs) for the different vehicle-vehicle and vehicle-pedestrian combinations. We find that in the absence of road safety interventions, the historical trend of initially rising and then falling fatalities observed in industrialized nations occurred only if motorization was through car ownership. In all other cases studied (scenarios dominated by scooter use, bus use, and mixed use), traffic fatalities rose monotonically. Fatalities per vehicle had a falling trend similar to that observed in historical data from industrialized nations. Regional adaptations of the model validated with local data can be used to evaluate the impacts of transportation planning and safety interventions, such as helmets, seat belts, and enforcement of traffic laws, on traffic fatalities.  相似文献   
2.
In the development of many diseases there are often associated random variables which continuously reflect the progress of a subject towards the final expression of the disease (failure). At any given time these processes, which we call stochastic covariates, may provide information about the current hazard and the remaining time to failure. Likewise, in situations when the specific times of key prior events are not known, such as the time of onset of an occult tumour or the time of infection with HIV-1, it may be possible to identify a stochastic covariate which reveals, indirectly, when the event of interest occurred. The analysis of carcinogenicity trials which involve occult tumours is usually based on the time of death or sacrifice and an indicator of tumour presence for each animal in the experiment. However, the size of an occult tumour observed at the endpoint represents data concerning tumour development which may convey additional information concerning both the tumour incidence rate and the rate of death to which tumour-bearing animals are subject. We develop a stochastic model for tumour growth and suggest different ways in which the effect of this growth on the hazard of failure might be modelled. Using a combined model for tumour growth and additive competing risks of death, we show that if this tumour size information is used, assumptions concerning tumour lethality, the context of observation or multiple sacrifice times are no longer necessary in order to estimate the tumour incidence rate. Parametric estimation based on the method of maximum likelihood is outlined and is applied to simulated data from the combined model. The results of this limited study confirm that use of the stochastic covariate tumour size results in more precise estimation of the incidence rate for occult tumours.  相似文献   
3.
Micro‐enterprises, i.e. firms with less than 10 employees, are traditionally the hardest to engage in learning; they are also least likely to participate in such measures as business advice and guidance provision and initiatives to support information communication technology (ICT) adoption. Through a community‐based initiative initially targeting parents (unemployed or employed) to participate in ICT, 30 micro‐enterprises were attracted to learning for the first time. These companies had carefully avoided similar initiatives taking place locally, which emphasized business success and growth; they had only participated in this ICT skills training because of their children. The paper takes a case study approach to evaluate the reasons for participation, explores barriers and implications for those organizing similar activities, and calls for a more holistic view of owners and managers of small firms as fathers, mothers, etc. rather than just as ‘entrepreneurs’.  相似文献   
4.
Urban elites are increasingly addressing local social problems though policies that turn their cities into tourist destinations. Often at the heart of these policies are new publicly financed sports stadiums. Ironically, this strategy is flourishing despite near-unanimous academic criticism, and increasing public skepticism, about this approach. Our research addresses this contradiction by exploring how and why powerful decisionmakers continue supporting publicly financed stadiums. We rely on local growth coalition theory to explore this topic because it offers analytical advantages, including looking beyond local sports teams as the focal point of these initiatives, addressing the variation in the outcomes of these initiatives, and acknowledging that policymakers are predisposed toward supporting these initiatives but that this predisposition does not always result in success.  相似文献   
5.
论企业的联合产权制度性质   总被引:8,自引:1,他引:7  
企业是一个以资源、能力与知识为基础的由要素所有者联合与劳动所有者联合相结合以创造、控制、分配 合作剩余的专业化生产性组织。联合产权制度是现代企业制度的普遍形式,也是现代企业制度的根本性质。  相似文献   
6.
Ecosystems are formed by organisations that jointly create a value proposition that a single firm could not create in isolation. To deliver this value proposition, the partners need a focal firm, the orchestrator, to be align them towards the joint value proposition. Thus, how orchestrators design the alignment structure of an ecosystem is at the very heart of the ecosystem concept – yet it has not been sufficiently addressed by extant research. This is all the more true for the question of how the design of an ecosystem is shaped depending on surrounding conditions. This paper applies a qualitative study with ten cases and, based on the attention-based view of the firm, contributes to research on ecosystems in several ways. First, it explains which ecosystem designs are beneficial under which conditions. Second, it elucidates the structure and activities within ecosystems and shows that start-ups can be just as good ecosystem orchestrators as incumbents. Third, it explains the circumstances under which single vs. multi orchestrator ecosystems occur. Fourth, it presents the conditions when incumbents or start-ups make better orchestrators. Finally, it is among the first studies to apply the attention-based view to business ecosystems, and shows that doing so yields intriguing insights into this emerging field of research.  相似文献   
7.
基于资源观的企业IT能力与企业绩效研究   总被引:4,自引:0,他引:4  
在企业广泛应用信息技术提高竞争能力之际,信息化如何给企业带来效益一直是国内外研究的热点问题.在回顾相关文献的基础上,利用基于资源观的概念框架分析企业IT资源,建立企业IT能力模型;采用配对样本比较和统计检验方法,对企业IT能力与企业绩效之间的关系进行实证分析.研究结果表明,具有卓越IT能力的企业会表现出更好的绩效,这些企业具有显著较高的营业净利率、总资产收益率、净资产收益率和人均净利润.企业不仅需要进行IT投资,更重要的是把IT投资内化为整个企业的IT能力,只有这样IT才会更好地给企业带来效益,这有助于指导中国企业信息化工程的建设和论证.  相似文献   
8.
经济制度与经济增长   总被引:3,自引:0,他引:3  
人们通常认为 ,经济增长是由资本、技术、劳动力等生产要素的投入带来的 ,不考虑或很少考虑经济增长的制度因素 ,而只是把它作为研究经济增长的已知的、既定的前提或外生的变量。然而 ,制度创新却能在物质生产要素不变尤其是技术不变时提高生产率 ,促进经济增长。制度因素对经济增长起着客观的制约作用。因此 ,研究经济增长不能撇开制度因素  相似文献   
9.
本文通过建立面板数据模型测度了农村居民消费对我国经济增长的影响效应,认为农村居民消费对我国经济增长具有正向促进作用但不够明显,分析了扩大农村居民消费需求促进经济增长所面临的障碍因素并提出了相应的对策建议。  相似文献   
10.
中国基础设施投资对经济增长波动的冲击效应分析   总被引:1,自引:1,他引:1  
基础设施是经济发展的重要影响因素,而“基础设施投资促进经济发展”这一主流观点已得到广泛共识,但人们对经济增长与基础设施的探讨仅局限于总量的分析框架,并未对基础设施的类型加以区分,更没发现经济发展的不同阶段对基础设施的需求结构也是不同的。而以“基础设施投资促进经济发展”为出发点,将基础设施投资细分为生产性、生活性、社会性基础设施投资,并分别讨论其对经济的影响。通过邹检验发现:自1994年以来,基础设施投资冲击改变了中国经济增长的特征。其结论是生产性、生活性基础设施对经济增长的影响是明确的、同步的,但社会性基础设施对经济增长的作用是不确定的。因此,加强社会性基础设施投资是一个渐进地逐步推进的过程。  相似文献   
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