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   137896篇
  免费   3218篇
  国内免费   1篇
财政金融   25848篇
工业经济   11601篇
计划管理   21905篇
经济学   29718篇
综合类   1470篇
运输经济   961篇
旅游经济   2501篇
贸易经济   23653篇
农业经济   6137篇
经济概况   17058篇
信息产业经济   8篇
邮电经济   255篇
  2021年   836篇
  2020年   1634篇
  2019年   2398篇
  2018年   2392篇
  2017年   2560篇
  2016年   2728篇
  2015年   2097篇
  2014年   3415篇
  2013年   15348篇
  2012年   4241篇
  2011年   4222篇
  2010年   3752篇
  2009年   4367篇
  2008年   3950篇
  2007年   3293篇
  2006年   3590篇
  2005年   3573篇
  2004年   3132篇
  2003年   2901篇
  2002年   2840篇
  2001年   2693篇
  2000年   2590篇
  1999年   2487篇
  1998年   2363篇
  1997年   2401篇
  1996年   2262篇
  1995年   2055篇
  1994年   2045篇
  1993年   2008篇
  1992年   2066篇
  1991年   1995篇
  1990年   1867篇
  1989年   1691篇
  1988年   1626篇
  1987年   1642篇
  1986年   1718篇
  1985年   2476篇
  1984年   2357篇
  1983年   2152篇
  1982年   2010篇
  1981年   1940篇
  1980年   1911篇
  1979年   1844篇
  1978年   1642篇
  1977年   1623篇
  1976年   1389篇
  1975年   1277篇
  1974年   1186篇
  1973年   1185篇
  1972年   898篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
881.
In this article, we examine the impact of 21 different types of scheduled macroeconomic news announcements on S&P 100 stock‐index option volume and implied volatility. We find that there is a 2‐h delay after the announcement before volume increases. However, there is an immediate increase in volatility, which slowly dissipates over several hours. Further analysis shows that most of the high volume and volatility after announcements come from the announcements that are considered bad news. That is, bad news creates high volatility and high volume, whereas good news elicits lower volume and is not associated with higher volatility. These results are not consistent with the predictions of any one model. We also find that the announcements that cause the largest reaction in the equity option market are Consumer Credit, Consumer Spending, Factory Inventories, NAPM, and Non‐Farm Payrolls. Six other announcements elicit a mild response. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:315–345, 2003  相似文献   
882.
We investigate intraday bid‐ask spreads (BAS), volatility, and trading activity of thinly traded equity index futures contracts on the Singapore Exchange. Contrary to previous findings, we find a rather flat BAS pattern during the trading day. However, consistent with past findings, an increase in risk widens the spread and a higher trading activity reduces it. When trading occurs in a day, spreads are reduced. No significant difference in volatility between days with and without trades was detected. When trades occur, quote revisions increase, and it is positively related to the number of trades. An increase in the number of quote revisions increases the likelihood of a transaction, and when quotes are current, revisions that are accompanied by trades carry new information. We provide evidence that contracts that are thinly traded may possess liquidity attributes as long as their price quotes remain current. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:455–486, 2003  相似文献   
883.
This article explores the price of continuously sampled Asian options. For geometric Asian options, we present pricing formulas for both backward‐starting and forward‐starting cases. For arithmetic Asian options, we demonstrate that the governing partial differential equation (PDE) cannot be transformed into a heat equation with constant coefficients; therefore, these options do not have a closed‐form solution of the Black–Scholes type, that is, the solution is not given in terms of the cumulative normal distribution function. We then solve the PDE with a perturbation method and obtain an analytical solution in a series form. Numerical results show that as compared with Zhang's ( 2001 ) highly accurate numerical results, the series converges very quickly and gives a good approximate value that is more accurate than any other approximate method in the literature, at least for the options tested in this article. Graphical results determine that the solution converges globally very quickly especially near the origin, which is the area in which most of the traded Asian options fall. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:535–560, 2003  相似文献   
884.
This article provides empirical evidence on the intraday relation between spot volatility and trading volume in the Spanish stock index futures market. GARCH methodology is used to estimate spot volatility. We analyze the potential relation between spot and futures trading volume and spot volatility by estimating the corresponding conditional density functions as proposed in Quah (1997). Our results reveal no significant link between those variables. Similar findings arise when expected and unexpected volume is considered. Our results suggest that derivative market is not a force behind episodes of significant spot jump volatility. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:841–858, 2003  相似文献   
885.
Unlike the traditional futures contract risk‐based approach to margining, new security futures contracts are margined under a strategy‐based margining system similar to that which applies in the equity options markets. As a result, these new margin requirements are potentially much less sensitive to changes in market conditions. This article performs a simulation to evaluate whether these alternative margining methodologies can be expected to produce comparable outcomes. The analysis suggests that a 1‐day settlement period will likely lead to collection of customer margins that are virtually always greater than that which its traditional risk‐based counterpart would require. A 4‐day settlement period would lead to margin requirements that both significantly under‐ and overmargin relative to a comparable risk‐based system. This study argues that exchanges may approach the preferred probability of customer exhaustion by managing margin settlement intervals. Thus, the new strategy‐based rules, in and of themselves, will not necessarily inhibit new security futures trading activity. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:989–1002, 2003  相似文献   
886.
An Internet presence is a critical early component in the process of building towards a fully operational and unified e‐commerce strategy. E‐commerce has significantly impacted logistics/supply chain strategies and the development and implementation of a website have become key issues for many firms within the transportation industry. This study provides an overview of website content within the motor carrier industry. Content analysis was used to assess the site design, informational content, and the interactive content of 152 motor carrier websites, and to compare the features offered on the Top 100 motor carrier firm websites with those offered on the sites of smaller carrier firms.  相似文献   
887.
Supplying customer demand from comparable alternate inventory locations when an item is out of stock at its primary stocking point creates a virtual inventory for that item. The expectation is that if more inventories can be drawn upon, the inventory for an item would be lower, the fill rate would be higher, or both. While generally true that safety stocks will be lower, regular stocks, on the other hand, may rise with such cross filling of demand. In this study, a methodology is developed that balances the cross filling effects on both regular and safety stocks for determining whether an inventoried item should be cross‐filled. An example and guidelines are given to show how the methodology can be simplified and applied in practice.  相似文献   
888.
Collaborative arrangements among members of the supply chain have received a great deal of interest in recent years as a means of reducing costs. One such arrangement is vendor managed inventory (VMI). VMI allows the vendor to make decisions concerning the quantity and timing of deliveries to the retailer. Such an arrangement offers the potential of a more efficient supply chain by removing the negative effects of retail ordering policies. A thorough review of the literature was conducted to identify factors likely to impact the performance of a VMI partnership. Computer simulation was used to study the effects of these factors from both the vendor's and retailer's perspectives. The results lend insight into the performance of VMI and guidance for managers as to the environments in which VMI is most effective.  相似文献   
889.
The primary purpose of this research was to investigate the effect of investment in information technology in a supply chain. The results of that investigation are presented by focusing on an empirically tested supply chain relationship model containing both behavioral and operational constructs. The four behavioral constructs represented in the model are relationship trust, relationship commitment, relationship dependence, and long‐term relationship orientation. The four operational constructs represented in the model are retailer investment in interorganizational information technology, perceived supplier investment in interorganizational information technology, logistics efficiency, and logistics effectiveness. Among other findings, the results of the investigation found that perceived supplier investment in interorganizational information technology has a significant and positive effect on logistics efficiency.  相似文献   
890.
The Internet has increased the level of importance of the end‐consumer market to transportation carriers. In two between subject experiments, carrier disclosure on retail merchant websites is examined as a strategic differentiation strategy. Predictions are offered concerning effects of carrier disclosure strategies on product delivery‐related expectations, consumer attitudes, and intentions to purchase a product online. Results from Study 1 reveal significant differences between disclosure and nondisclosure of the carrier for numerous product delivery‐related variables, as well as many differences between the six carriers examined in this first study. Study 2 extends these findings by showing that providing consumers with a choice of carrier leads to increased levels of satisfaction with the online experience and greater willingness to buy, relative to nondisclosure and disclosure strategies.  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