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   9826篇
  免费   483篇
  国内免费   103篇
财政金融   721篇
工业经济   898篇
计划管理   4569篇
经济学   857篇
综合类   1122篇
运输经济   55篇
旅游经济   56篇
贸易经济   1043篇
农业经济   424篇
经济概况   667篇
  2024年   10篇
  2023年   107篇
  2022年   149篇
  2021年   251篇
  2020年   218篇
  2019年   114篇
  2018年   123篇
  2017年   129篇
  2016年   160篇
  2015年   329篇
  2014年   870篇
  2013年   689篇
  2012年   984篇
  2011年   1333篇
  2010年   1067篇
  2009年   569篇
  2008年   660篇
  2007年   587篇
  2006年   522篇
  2005年   406篇
  2004年   315篇
  2003年   220篇
  2002年   145篇
  2001年   111篇
  2000年   82篇
  1999年   68篇
  1998年   39篇
  1997年   34篇
  1996年   19篇
  1995年   12篇
  1994年   17篇
  1993年   15篇
  1992年   12篇
  1991年   13篇
  1990年   7篇
  1989年   6篇
  1988年   2篇
  1987年   1篇
  1985年   5篇
  1984年   2篇
  1983年   4篇
  1982年   3篇
  1981年   1篇
  1980年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
With advances in new technology, various formats of online advertising (e.g., in-stream video advertising) often force e-consumers to watch the advertisement during their goal-oriented activities, and this advertising interruption often makes them feel intruded upon and irritated. To reduce such negative reactions toward involuntary advertising exposures, this study examines whether offering e-consumers the option to choose advertising content can influence ad effectiveness in different degrees of forced exposure circumstance. Using a 2 (advertising content control: customization option vs. no option) × 2 (level of forced exposure: pre-rolls vs. rich media banners) factorial experiment, the researcher noted that advertising customization features generate a greater sense of relevance and increased advertising memory, which in turn may lead to more positive attitudes toward the ad regardless of the levels of forced exposure. The findings have theoretical and practical implications on the use of involuntary advertising interruptions in the web interface.  相似文献   
2.
Facebook has become an important platform for a brand–consumer relationship channel. The current study investigates the influence of perceived socialness and its effect on consumers’ attitude toward brands. Participants (N = 404) were recruited in a large southeast university. A 2 (socialness: high vs. low)?×?2 (feedback control: high vs. low)?×?2 (brand image: high vs. low) between-subject design was conducted. The results of this study identified three important findings. First, high (vs. low) socialness elicited higher perceived relationship commitment, brand trust, and more favorable brand attitude. Second, the effect of socialness on brand attitude was moderated by brand image (positive vs. negative). Third, the mediation analysis showed that the effect of socialness (high vs. low) on brand attitude was fully mediated by perceived relationship commitment and brand trust.  相似文献   
3.
为了解决宏蜂窝与飞蜂窝构成的两层异构网络上行干扰与资源分配问题,提出了一种在认知型飞蜂窝的双层异构网中结合子信道分配和功率控制进行资源分配的框架。通过对异构网中跨层干扰问题进行分析与建模,将求解最优子信道分配矩阵和用户发射功率矩阵作为干扰管理问题的解决方法。模型中认知型飞蜂窝网络子信道和飞蜂窝网络用户构成非合作博弈,双方利用效用函数最优值进行匹配,构成初始信道分配矩阵;再由接入控制器根据接入条件从初始信道分配矩阵中筛选用户,并优化接入用户的发射功率矩阵,得到最优子信道分配矩阵和功率矩阵。仿真结果表明,优化框架提高了双层异构网络中飞蜂窝网络用户的吞吐量和接入率,降低了异构网中跨层干扰。  相似文献   
4.
Post-Keynesian institutionalist economists like Wallace Peterson and John Kenneth Galbraith recognized that the impact of uncertainty on economic wellbeing depends in part on the degree of control people have over the sources and consequences of it. Given the inability of government and other large institutions to reduce uncertainty or to provide citizens with the ability to manage it, mediating structures are considered as an alternative means of promoting economic security. The article concludes by describing and evaluating several of these alternatives.  相似文献   
5.
Factors affecting subjective well-being and their gross effect measurement have been widely studied. However, how people derive utility from these factors has not been fully explored. This article provides a way to decompose the gross effect of major determinants on life satisfaction into direct and indirect effects and make inference for the latter. Because the indirect effect is nonlinear in parameters associated with different models in an equation system, it creates a problem in estimating the standard error. Besides, the categorical nature in survey data further introduces bias to the covariance estimation even asymptotically. To address these issues without knowing the form of heteroskedasticity under the null hypothesis, we propose to extend the wild bootstrap procedure in this particular context. Its robustness against various data properties is validated via several simulation experiments. Using three recent waves of World Values Survey, we find that the relative importance of life control has significantly increased recently, and endowing citizens with the right to enjoy their freedoms and liberties is a more effective policy in raising life satisfaction than promoting national income.  相似文献   
6.
Literature shows that female (male) managers are more likely to adopt a transformational (transactional) leadership style, as well as make greater (lesser) use of information for decision-making. We draw on this research to investigate whether gender is related to a manager's use of management control systems (MCS) and performance measures. We surveyed the head of school of all schools across all Australian public universities. Our results indicate that females use MCS in an interactive manner to a greater extent than their male counterparts and make greater use of non-financial performance measures. We conclude with contributions to theory and practice.  相似文献   
7.
刘家荣  韦大松 《现代食品》2020,2(4):9-12,15
研发适用于滤袋式除尘器粉尘爆炸危险源信号的实时检测及预警系统。该系统综合应用工业控制、PLC控制、智能测控终端无线传输、云平台数据管理等技术。采用传感器分别监测除尘器运行时的进出风口压差、除尘器运行状态、高压脉冲喷吹压力和箱体温度。当监测信号不在系统预设的合理范围时,PLC输出就地预警信号,监测信号也可通过无线传输模块上传到云平台。运用云平台的数据分析功能,实现除尘器运行状态系统化监测和综合管理。  相似文献   
8.
In recent years, labor-intensive agricultural products from developing countries have exhibited inferior performance in international trade due to quality and safety incidents, among which pesticide residue is a major issue. Aiming to improve food quality and safety in the context of cooperatives, we introduced three categories of control measures: outcome control, process control and social control. Based on the Pre-Harvest Interval Standard (PHIS), we selected three indices, farmers’ implementation rate of PHIS, absolute distance to PHIS and relative distance to PHIS, to evaluate appropriateness of pesticides use, reduction of pesticide residue and safety improvements of agricultural products. By using random sampling survey data, we empirically analyzed the marginal effects of control measures and their combinations on food quality and safety standards. The empirical results show that implementing process control, namely, unified production standards or supply of unified agricultural inputs, can comprehensively improve farmers’ implementation rate of PHIS, absolute distance and relative distance to PHIS respectively by 34.9%, 3.2 days and 46.0% on average. While the effects of outcome control (safety inspection) and social control (bonus-penalty incentive or training) are restricted to other measures. Therefore, we suggest cooperatives should take farmers’ features, implementation conditions and the effects of control measures into consideration in order to make a sustainable management plan for improving food quality and safety and enhancing competitiveness in international markets.  相似文献   
9.
In this paper, we generalize recursive utility to include lifetime uncertainty and utility from bequest. The generalization applies to discrete-time as well as continuous-time recursive utility, and it is an important step forward in the development of recursive utility. We formalize the problem of optimal consumption, investment, and life insurance choice under recursive utility, and we state a verification theorem with a generalized Hamilton-Jacobi-Bellman equation. Our generalization of recursive utility allows us to study optimal consumption, investment, and life insurance choice under separation of (market) risk aversion, elasticity of inter-temporal substitution, and elasticity of substitution between bequest and future utility. The separation gives rise to hump-shaped consumption patterns as observed in realized consumption.  相似文献   
10.
针对采用时隙ALOHA算法的无线Ad Hoc网络,考虑数据包到达的动态性与数据包传输的随机性,以最大化吞吐量为目标,同时满足数据队列稳定性,构建了关于接纳控制与竞争接入的随机优化问题。由于在时隙ALOHA算法中数据包传输的最优概率取决于无线Ad Hoc网络中数据队列非空的活跃节点数,提出了一种基于活跃节点数预测的时隙ALOHA算法。该算法要求无线Ad Hoc网络中的所有发送节点实时地侦听通信信道的忙闲状态,计算基于信道状态的活跃节点数条件期望,从而动态地预测无线Ad Hoc网络在不同时刻的活跃节点数,达到网络节点依据局部网络状态信息自适应地优化数据包传输概率的目的。仿真结果表明,所提算法能够有效估计无线Ad Hoc网络在每个时隙的活跃节点数,从而显著提升网络吞吐量并且降低数据包的平均排队时延。  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