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排序方式: 共有213条查询结果,搜索用时 31 毫秒
1.
从微分方程的角度出发 ,分三个方面讨论了一类收敛级数求和问题的具体解法。  相似文献   
2.
运用Halliday系统功能语法的观点和方法,主要探讨了语篇功能赖以实现的主位系统,分析主位结构和主位推进程序在实现语篇的衔接和连贯中的作用、所具有的文体功能以及主位的选择和使用表达说话者的不同目的的关系。  相似文献   
3.
As flood risks grow worldwide, a well‐designed insurance program engaging various stakeholders becomes a vital instrument in flood risk management. The main challenge concerns the applicability of standard approaches for calculating insurance premiums of rare catastrophic losses. This article focuses on the design of a flood‐loss‐sharing program involving private insurance based on location‐specific exposures. The analysis is guided by a developed integrated catastrophe risk management (ICRM) model consisting of a GIS‐based flood model and a stochastic optimization procedure with respect to location‐specific risk exposures. To achieve the stability and robustness of the program towards floods with various recurrences, the ICRM uses stochastic optimization procedure, which relies on quantile‐related risk functions of a systemic insolvency involving overpayments and underpayments of the stakeholders. Two alternative ways of calculating insurance premiums are compared: the robust derived with the ICRM and the traditional average annual loss approach. The applicability of the proposed model is illustrated in a case study of a Rotterdam area outside the main flood protection system in the Netherlands. Our numerical experiments demonstrate essential advantages of the robust premiums, namely, that they: (1) guarantee the program's solvency under all relevant flood scenarios rather than one average event; (2) establish a tradeoff between the security of the program and the welfare of locations; and (3) decrease the need for other risk transfer and risk reduction measures.  相似文献   
4.
中国长期受到自然灾害的困扰,建立适合国情的巨灾保险体制已经成为必然。分析中国巨灾保险在供给和需求两方面均呈现不足状态的原因,借鉴国际上巨灾保险体制发展较好国家的经验,认为建立完善的巨灾保险体制需要从建立完备的法律体系、发展繁荣的巨灾保险市场和培养多层次的巨灾风险管理体系几个方面入手。从目前情况来看,应该从建立完善的法律体系、发展再保险市场、建立巨灾风险基金和发展政府巨灾债券几个方面着手,建设多层次的、适合中国国情的巨灾保险体制。  相似文献   
5.
对农产品物流产业发展水平进行客观、准确的分析与评估,可为政府部门优化与调整产业发展、合理制定产业规划提供科学依据。运用突变级数法与离差最大化法构建农产品物流产业评估模型,并选取广东和山东两省20102014年相关数据对构建的评估模型进行实例分析。结果表明:广东省农产品物流产业发展的优势主要体现在信息化水平与经济基础两方面,基础设施建设则是当前制约其产业发展的关键因素;而庞大的产业规模是现阶段支撑山东省农产品物流产业发展的重要力量。改进的突变级数评估模型既克服了主观赋权的局限,又不失科学性和合理性,计算简单,具有重要实用价值。  相似文献   
6.
在话语分析中,不同的分析者对于主位有着不同的认识,拟根据韩礼德对主位的定义,着重探讨主位推进模式在话语分析中的作用,尤其是在书面语篇中的作用。  相似文献   
7.
We describe a regression-based approach to the modelling of age-, order-, and duration-specific period fertility, using retrospective survey data. The approach produces results that are free of selection biases and can be used to study differential fertility. It is applied to Demographic and Health Survey data for Ethiopia, Kenya, Tanzania, and Zimbabwe to investigate differential trends in fertility by education. Parity progression fell and the intervals following each birth lengthened between the 1970s and 2000s in all four countries. Fertility fell most among women with secondary education. In contrast to other world regions, postponement of successive births for extended periods accounted for much of the initial drop in fertility in these African countries. However, family size limitation by women with secondary education in Ethiopia and Kenya and longer birth spacing in Zimbabwe also played significant roles. Thus, birth control is being adopted in Eastern Africa in response to diverse changes in fertility preferences.  相似文献   
8.
Most studies that have examined whether a child’s death influences parental relationship stability have used small-scale data sets and their results are inconclusive. A likely reason is that child loss affects not only the risk of parental separation, but also the risk of having another child. Hence parity progression and separation must be treated as two competing events in relation to child loss. The analysis in this paper used Finnish register data from 1971 to 2003, covering over 100,000 married couples whose durations of both first marriage and parenthood could be observed. We ran parity-specific Cox regressions in which process time started from the birth of each additional child. All marriages included women of childbearing age, none of whom had experienced any child death on entering the analysis. We find that child loss only modestly influences the divorce risk, whereas its effect on the risk of parity progression is considerable.  相似文献   
9.
This study examined biological sex differences in the development of mild cognitive impairment (MCI) and probable Alzheimer’s disease (AD) development as predicted by changes in the hippocampus or white matter hyperintensities. A secondary data analysis of the National Alzheimer’s Coordinating Center Uniform Data Set was conducted. We selected samples of participants with normal cognition at baseline who progressed to MCI (n = 483) and those who progressed to probable AD (n = 211) to determine if hippocampal volume or white matter hyperintensities (WMH) at baseline predicted progression to probable AD or MCI and whether the rate of progression differed between men and women. The survival analyses indicated that changes in hippocampal volumes affected the progression to probable AD (HR = 0.535, 95% CI [0.300–0.953]) only among women. White men had an increased rate of progression to AD (HR = 4.396, CI [1.012–19.08]; HR = 4.665, 95% CI [1.072–20.29]) compared to men in other race and ethnic groups. Among women, increases in hippocampal volume ratio led to decreased rates of progressing to MCI (HR = 0.386, 95% CI [0.166–0.901]). Increased WMH among men led to faster progression to MCI (HR = 1.048. 95% CI [1.011–1.086]). Women and men who were older at baseline were more likely to progress to MCI. In addition, results from longitudinal analyses showed that women with a higher CDR global score, older age at baseline, or more disinhibition symptoms experienced higher odds of MCI development. Changes in hippocampal volumes affect the progression to or odds of probable AD (and MCI) more so among women than men, while changes in WMH affected the progression to MCI only among men.  相似文献   
10.
Disabled people are under-represented in higher education (HE), especially in senior posts. This article reports research on the perspectives of career progression into leadership held by disabled staff in one post-1992 university. Findings indicated that some participants were already engaged in leadership or aspired to such roles, and reported positive experiences. However, participants also experienced barriers to progression, including a lack of awareness of equality and diversity among managers and colleagues, inadequate professional development opportunities and the competitive organisational culture of management that could impact on their health and work–life balance. We conclude that disabled staff in HE do not yet have equal opportunities for progression into leadership roles compared with their non-disabled peers. There is a need for realignment of the culture of leadership and management to make it more compatible with the full inclusion of disabled staff in HE such that their unique contributions are valued.  相似文献   
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