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   158766篇
  免费   4483篇
  国内免费   27篇
财政金融   26982篇
工业经济   11768篇
计划管理   23135篇
经济学   31271篇
综合类   1539篇
运输经济   975篇
旅游经济   2508篇
贸易经济   24403篇
农业经济   6261篇
经济概况   17422篇
水利工程   16652篇
信息产业经济   7篇
邮电经济   353篇
  2021年   1111篇
  2020年   1847篇
  2019年   2660篇
  2018年   2904篇
  2017年   2933篇
  2016年   3231篇
  2015年   2450篇
  2014年   3875篇
  2013年   16532篇
  2012年   5006篇
  2011年   4916篇
  2010年   4216篇
  2009年   4823篇
  2008年   4569篇
  2007年   4130篇
  2006年   4394篇
  2005年   4313篇
  2004年   3978篇
  2003年   3323篇
  2002年   3270篇
  2001年   3151篇
  2000年   3002篇
  1999年   2837篇
  1998年   2724篇
  1997年   2755篇
  1996年   2608篇
  1995年   2389篇
  1994年   2413篇
  1993年   2397篇
  1992年   2483篇
  1991年   2361篇
  1990年   2166篇
  1989年   1995篇
  1988年   1898篇
  1987年   1914篇
  1986年   1937篇
  1985年   2739篇
  1984年   2679篇
  1983年   2482篇
  1982年   2356篇
  1981年   2271篇
  1980年   2274篇
  1979年   2212篇
  1978年   1988篇
  1977年   1865篇
  1976年   1696篇
  1975年   1538篇
  1974年   1420篇
  1973年   1419篇
  1972年   1117篇
排序方式: 共有10000条查询结果,搜索用时 546 毫秒
131.
In the retail industry, backroom inventories are typically associated with higher labor costs and greater operational complexity. Thus, retailers look for ways to eliminate backroom inventories. A heuristic used for this purpose is the pack‐and‐a‐half rule which suggests that the shelf space allocated for a product should be at least 50% larger than the case pack quantity in which the product is delivered. Despite its popularity among retailers, the pack‐and‐a‐half rule has been ignored in the academic literature. We introduce the pack‐and‐a‐half rule, assess its impact on a retailer's profits, identify cost, demand, and product characteristics driving this impact, and propose a modification. Based on an analysis of data obtained from a retailer on 1,986 SKUs in 20 categories, we find that the pack‐and‐a‐half rule decreases a retailer's profits, on average, by 10% when applied uniformly across all SKUs. Further, this decrease is significantly affected by product depth, product width, demand elasticity, case pack quantity, and inventory carrying cost. Finally, we develop a set of modifications based on these variables where the pack‐and‐a‐half rule is applied selectively and in a stepwise fashion. These modifications limit the decrease in a retailer's profits to a range between 6% and 7%.  相似文献   
132.
Motor carrier safety is an important concern of shippers, carriers, policy makers, consignees, insurance providers, and the motoring public. One aspect of carrier safety that has garnered substantial attention is whether carriers making greater use of owner–operators are more or less safe vis‐à‐vis carriers making greater use of employee drivers. Currently, conflicting theoretical predictions exist regarding the direction of this relationship. In this article, we offer a reconciliation of the alternative theoretical predictions by developing a coherent theory that merges sociological rational choice theory and theory regarding motor carrier safety. We subject our theory to empirical testing by fitting a series of seemingly unrelated regression models to a vector of safety measures tracked as part of the Federal Motor Carrier Safety Administration's Compliance, Safety, and Accountability program. Our results are consistent with our proposed theory of owner—operator safety and provide meaningful theoretical and managerial implications and directions for future research.  相似文献   
133.
134.
We investigate whether firms restructure board composition to align with changes in their contracting environment. Board size and independence increase with firm complexity, consistent with theoretical predictions. However, the hypothesized negative relation between board independence and information costs is evident only for firms completing acquisitions. Furthermore, board independence increases to offset increases in CEO power in a sample of firms making acquisitions, but decreases when CEO power increases in a large cross‐section of firms. We conclude that after the Sarbanes–Oxley Act of 2002, firms face constraints adjusting to target board structure, but these constraints can be mitigated by a shock to the contracting environment via acquisition.  相似文献   
135.
136.
Power Technology and Engineering - The experimental results on retaining reinforced-concrete walls reinforced with anchor ties and carbon composite materials on the face side of hydraulic...  相似文献   
137.
138.
In this paper, we focus on the question to what extent machine learning (ML) tools can be used to support systematic literature reviews. We apply a ML approach for topic detection to analyze emerging topics in the literature—our context is accounting and finance research in the Asia–Pacific region. To evaluate the robustness of the approach, we compare findings from the automated ML approach with the results from a manual analysis of the literature. The automated approach uses a keyword algorithm detection mechanism whereby the manual analysis uses common techniques for qualitative data analysis, that is, triangulation between researchers (expert judgement). From our paper, we conclude that both methods have strengths and weaknesses. The automated analysis works well for large corpora of text and provides a very standardized and non-biased way of analyzing the literature. However, the human researcher is potentially better equipped to evaluate current issues and future trends in the literature. Overall, the best results might be achieved when a variety of tools are used together.  相似文献   
139.
140.
Estimation of earth-fill dam height and dimension of spillway are strongly depend on accurate evaluation of dam overtopping reliability. Ideally, whole random and effective variables on overtopping should be considered for dam overtopping reliability assessment. However, taking into account all affecting random variables as well as overtopping reliability assessment using algorithms such as Monte Carlo (MC) could be excessively time consuming and impossible in some cases. In this study, new approach has been introduced as conditional reliability method and it has been tried to reduce the simulations time significantly by using combination of rainfall threshold theory, SUFI (Sequential Uncertainty Fitting) and MC methods. According two defined indexes, the obtain results shown, the relative error of new approach in computation of Jamishan dam overtopping reliability is less than 0.23%. Also, time saving in new method against to regular MC method is more than 87%. So, the new introduced method has more efficiency with acceptable accuracy for assessment of dam overtopping reliability. In addition, among hydrological and hydraulic uncertainties, hydrological uncertainties have more effect on overtopping reliability.  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