首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7361篇
  免费   440篇
  国内免费   117篇
管理学   2827篇
民族学   12篇
人口学   90篇
丛书文集   293篇
理论方法论   397篇
综合类   2958篇
社会学   514篇
统计学   827篇
  2024年   14篇
  2023年   131篇
  2022年   98篇
  2021年   109篇
  2020年   253篇
  2019年   247篇
  2018年   237篇
  2017年   283篇
  2016年   266篇
  2015年   272篇
  2014年   410篇
  2013年   717篇
  2012年   467篇
  2011年   442篇
  2010年   365篇
  2009年   349篇
  2008年   358篇
  2007年   373篇
  2006年   382篇
  2005年   374篇
  2004年   302篇
  2003年   259篇
  2002年   204篇
  2001年   197篇
  2000年   110篇
  1999年   101篇
  1998年   60篇
  1997年   53篇
  1996年   50篇
  1995年   43篇
  1994年   59篇
  1993年   43篇
  1992年   33篇
  1991年   31篇
  1990年   38篇
  1989年   23篇
  1988年   36篇
  1987年   22篇
  1986年   20篇
  1985年   13篇
  1984年   18篇
  1983年   18篇
  1982年   17篇
  1981年   17篇
  1980年   1篇
  1979年   1篇
  1977年   1篇
  1975年   1篇
排序方式: 共有7918条查询结果,搜索用时 375 毫秒
121.
The management of natural- and human-induced wildland fires is an intricate process that must balance two considerations: that of fire as a necessary natural disturbance and that of the risks that fire poses. Reconciling tradeoffs between these risks and benefits is contingent upon informed, directed, and two-way communication between wildland fire managers and stakeholders. In an effort to aid with the design of such a communication effort, this study used mental models research to determine the unique wildland fire information and decision-making needs of stakeholders living at the wildland-urban interface of a fire-prone area. While the analysis revealed many similarities in how stakeholders conceptualized the risks and benefits of wildland fire, many misconceptions and important gaps in understanding on the part of both expert and nonexpert respondents were identified.  相似文献   
122.
Wide Diameters of Cartesian Product Graphs and Digraphs   总被引:1,自引:1,他引:1  
In graph theory and study of fault tolerance and transmission delay of networks, connectivity and diameter of a graph are two very important parameters and have been deeply studied by many authors. Wide diameter combining connectivity with diameter is a more important parameter to measure fault tolerance and efficiency of parallel processing computer networks and has received much attention in the recent years. Diameter with width k of a graph G is defined as the minimum integer d for which between any two distinct vertices in G there exist at least k internally disjoint paths of length at most d. In the present paper, the tight upper bounds of wide diameter of the Cartesian product graphs are obtained. Some known results can be deduced or improved from ours.  相似文献   
123.
风险预算在国外正赢得学术界、养老基金和资产管理领域等许多方面的广泛关注,并认为是组合管理的一种创新。国内投资者日益认识到投资组合管理与风险控制的重要意义,并近乎成为他们的第一要务。本文利用因子模型,通过风险预算这一投资管理和风险控制技术与方法,讨论投资组合因子风险分解并进行实证分析。  相似文献   
124.
社会网络对民间金融风险的影响已被广泛认可,但是,究竟什么样的网络结构有抑制风险的作用,什么样的网络结构有扩增风险的作用?以资金互助会为例,将互助会涉及的社会网络按结构特征分为单个会的会内网络和多个会的会间网络,研究可知:(1)越紧密的会内网络结构以及越大的网络规模越有利于民间金融风险的控制。(2)跨会网络具有抑制和扩增风险两种作用,它是协同监督和惩罚机制生效的基础,因而对风险具有控制作用,但这种作用只在中介成员为会首时才显著;同时,它也构成了风险传播的通道,导致资金被分散到多个会中,因而提升了系统性风险。  相似文献   
125.
    
选取14家上市商业银行2008—2016年的股票日度收益率数据,构建ARMA-GARCH-CoVaR模型,测度各家上市商业银行对整个银行体系的风险贡献程度以及商业银行之间的风险溢出强度。实证结果表明:每家商业银行都存在风险溢出效应,但不同商业银行对系统性风险的贡献程度存在明显差异,商业银行的系统性风险溢出程度与其自身风险水平的相关性较弱。值得注意的是,大型国有商业银行自身风险水平较低,但对银行系统性风险溢出强度最大;不同商业银行之间也存在风险溢出效应,但溢出程度呈现明显的非对称性,国有商业银行、城市商业银行对其关联银行的风险溢出大于股份制商业银行。此外,国内外经济金融形势对我国银行业系统性风险溢出具有重要影响,应将重大经济金融事件纳入到银行系统性风险的动态监测过程中。  相似文献   
126.
This study investigated the extent to which tolerance of uncertainty affects the relationship between happenstance skills and career satisfaction via career decision self‐efficacy. Moderated mediation analysis was conducted on data collected from 321 graduates (175 men, 146 women) of Korean universities making the school‐to‐work transition. Results showed that career decision self‐efficacy fully mediated the relationship between happenstance skills and career satisfaction. Furthermore, the moderation effect of tolerance of uncertainty had a significant impact on the relationship between happenstance skills and career decision self‐efficacy. Tolerance of uncertainty should be considered an important variable in happenstance career theory and intervention. Unplanned influences should also be considered important factors in the career decision‐making process.  相似文献   
127.
Melamine contamination of food has become a major food safety issue because of incidents of infant disease caused by exposure to this chemical. This study was aimed at establishing a safety limit in Taiwan for the degree of melamine migration from food containers. Health risk assessment was performed for three exposure groups (preschool children, individuals who dine out, and elderly residents of nursing homes). Selected values of tolerable daily intake (TDI) for melamine were used to calculate the reference migration concentration limit (RMCL) or reference specific migration limit (RSML) for melamine food containers. The only existing values of these limits for international standards today are 1.2 mg/L (0.2 mg/dm2) in China and 30 mg/L (5 mg/dm2) in the European Union. The factors used in the calculations included the specific surface area of food containers, daily food consumption rate, body weight, TDI, and the percentile of the population protected at a given migration concentration limit (MCL). The results indicate that children are indeed at higher risk of melamine exposure at toxic levels than are other groups and that the 95th percentile of MCL (specific surface area = 5) for children aged 1–6 years should be the RMCL (0.07 mg/dm2) for protecting the sensitive and general population.  相似文献   
128.
Anthropogenic climate change information tends to be interpreted against the backdrop of initial environmental beliefs, which can lead to some people being resistant toward the information. In this article (N = 88), we examined whether self‐affirmation via reflection on personally important values could attenuate the impact of initial beliefs on the acceptance of anthropogenic climate change evidence. Our findings showed that initial beliefs about the human impact on ecological stability influenced the acceptance of information only among nonaffirmed participants. Self‐affirmed participants who were initially resistant toward the information showed stronger beliefs in the existence of climate change risks and greater acknowledgment that individual efficacy has a role to play in reducing climate change risks than did their nonaffirmed counterparts.  相似文献   
129.
Introduction and spread of the parasite Myxobolus cerebralis, the causative agent of whirling disease, has contributed to the collapse of wild trout populations throughout the intermountain west. Of concern is the risk the disease may have on conservation and recovery of native cutthroat trout. We employed a Bayesian belief network to assess probability of whirling disease in Colorado River and Rio Grande cutthroat trout (Oncorhynchus clarkii pleuriticus and Oncorhynchus clarkii virginalis, respectively) within their current ranges in the southwest United States. Available habitat (as defined by gradient and elevation) for intermediate oligochaete worm host, Tubifex tubifex, exerted the greatest influence on the likelihood of infection, yet prevalence of stream barriers also affected the risk outcome. Management areas that had the highest likelihood of infected Colorado River cutthroat trout were in the eastern portion of their range, although the probability of infection was highest for populations in the southern, San Juan subbasin. Rio Grande cutthroat trout had a relatively low likelihood of infection, with populations in the southernmost Pecos management area predicted to be at greatest risk. The Bayesian risk assessment model predicted the likelihood of whirling disease infection from its principal transmission vector, fish movement, and suggested that barriers may be effective in reducing risk of exposure to native trout populations. Data gaps, especially with regard to location of spawning, highlighted the importance in developing monitoring plans that support future risk assessments and adaptive management for subspecies of cutthroat trout.  相似文献   
130.
In risk assessment, the moment‐independent sensitivity analysis (SA) technique for reducing the model uncertainty has attracted a great deal of attention from analysts and practitioners. It aims at measuring the relative importance of an individual input, or a set of inputs, in determining the uncertainty of model output by looking at the entire distribution range of model output. In this article, along the lines of Plischke et al., we point out that the original moment‐independent SA index (also called delta index) can also be interpreted as the dependence measure between model output and input variables, and introduce another moment‐independent SA index (called extended delta index) based on copula. Then, nonparametric methods for estimating the delta and extended delta indices are proposed. Both methods need only a set of samples to compute all the indices; thus, they conquer the problem of the “curse of dimensionality.” At last, an analytical test example, a risk assessment model, and the levelE model are employed for comparing the delta and the extended delta indices and testing the two calculation methods. Results show that the delta and the extended delta indices produce the same importance ranking in these three test examples. It is also shown that these two proposed calculation methods dramatically reduce the computational burden.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号