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   37891篇
  免费   601篇
财政金融   6582篇
工业经济   2541篇
计划管理   6140篇
经济学   8388篇
综合类   647篇
运输经济   205篇
旅游经济   384篇
贸易经济   7689篇
农业经济   949篇
经济概况   4323篇
信息产业经济   46篇
邮电经济   598篇
  2021年   142篇
  2020年   248篇
  2019年   326篇
  2018年   2768篇
  2017年   2512篇
  2016年   1694篇
  2015年   397篇
  2014年   591篇
  2013年   2343篇
  2012年   1116篇
  2011年   2619篇
  2010年   2401篇
  2009年   2200篇
  2008年   2122篇
  2007年   2371篇
  2006年   610篇
  2005年   837篇
  2004年   947篇
  2003年   1053篇
  2002年   689篇
  2001年   499篇
  2000年   523篇
  1999年   427篇
  1998年   401篇
  1997年   399篇
  1996年   392篇
  1995年   329篇
  1994年   331篇
  1993年   374篇
  1992年   335篇
  1991年   329篇
  1990年   312篇
  1989年   288篇
  1988年   276篇
  1987年   240篇
  1986年   293篇
  1985年   384篇
  1984年   360篇
  1983年   338篇
  1982年   292篇
  1981年   281篇
  1980年   304篇
  1979年   254篇
  1978年   218篇
  1977年   200篇
  1976年   179篇
  1975年   160篇
  1974年   134篇
  1973年   143篇
  1972年   106篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Innovation is the engine of development for enterprises, and there is an increasing trend to adopt an open innovation strategy. However, how to manage external resources in an open, collaborative and complementary manner, and in a shared environment that will yield the greatest networking effects, it is a challenging task. Because there is no such a satisfactory model for an open innovation strategy that combine operational mechanisms with the management of, external resources. Thhis article tries to fill the gap by adopting a resource-based perspective to construct an overall open innovation (OOI) business model. In this model, external resources are classified as industrial and non-industrial entities, to enable the identification of the interaction methods between manufacturing enterprises and external resources. The management of external resources involved in a Technology Open Innovation (TOI) cycle is given particular attention that includes: 1) the classification of the external resources of a TOI, 2) the general mechanisms extracted to promote qualified resources in and unqualified resources out, and 3) a business model to conceptualize the collaboration between enterprises and external resources. A case study of TOI is also provided to empirically verify its feasibility. This paper contributes to the literature by providing an original operational model and mechanism design for an open innovation strategy that is capable of managing external resources effectively.  相似文献   
952.
This study examines the association between tax avoidance and ex ante cost of equity capital. Based on prior research, we develop two proxies for investors’ expectations of tax avoidance and explore whether deviations from those expectations result in higher ex ante cost of equity capital. We find that the ex ante cost of equity capital increases with tax avoidance that is either below or above investor expectations and that the increase is larger for tax avoidance that exceeds investors’ expectations. We then examine whether firms that alter their future tax avoidance exhibit a lowering of their ex ante cost of equity capital and find that tax avoidance decreases (increases) from the prior year for firms that were above (below) investors’ expectations in the prior year. These results are consistent with the trade‐off suggested by the Scholes and Wolfson framework and reinforce the notion that balancing tax benefits and non‐tax costs is an important feature of firms’ tax planning.  相似文献   
953.
The criminal nature of narcotics complicates the direct assessment of a drug community, while having a good understanding of the type of people drawn or currently using drugs is vital for finding effective intervening strategies. Especially for the Russian Federation this is of immediate concern given the dramatic increase it has seen in drug abuse since the fall of the Soviet Union in the early nineties. Using unique data from the Russian social network ‘LiveJournal’ with over 39 million registered users worldwide, we were able for the first time to identify the on-line drug community by context sensitive text mining of the users’ blogs using a dictionary of known drug-related official and ‘slang’ terminology. By comparing the interests of the users that most actively spread information on narcotics over the network with the interests of the individuals outside the on-line drug community, we found that the ‘average’ drug user in the Russian Federation is generally mostly interested in topics such as Russian rock, non-traditional medicine, UFOs, Buddhism, yoga and the occult. We identify three distinct scale-free sub-networks of users which can be uniquely classified as being either ‘infectious’, ‘susceptible’ or ‘immune’.  相似文献   
954.
Providing nutritious and environmentally sustainable food to all people at all times is one of the greatest challenges currently facing society. This problem is particularly acute in Africa where an estimated one in four people still lack adequate food to sustain an active and healthy life. In this study, we consider the potential impact of future population growth and climate change on food security in Africa, looking ahead to 2050. A modelling framework termed FEEDME (Food Estimation and Export for Diet and Malnutrition Evaluation) was used which was characterized to model the impacts of future climate changes (utilizing the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios projections) and projected population growth on food availability and subsequent undernourishment prevalence in 44 African countries. Our results indicate that projected rapid population growth will be the leading cause of food insecurity and widespread undernourishment across Africa. Very little to no difference in undernourishment projections were found when we examined future scenarios with and without the effects of climate change, suggesting population growth is the dominant driver of change. Various adaptation options are discussed, such as closing the yield gap via sustainable intensification and increasing imports through trade and aid agreements. These strategies are likely to be critical in preventing catastrophic future food insecurity.  相似文献   
955.
Digitalisation of the health care system proceeds. Therefore it is to be expected that telemedicine applications will also be introduced into health care. Currently, the number of telemedicine applications in Germany is low and it is also scarce in comparison to foreign countries. This is striking because it is usually supposed that telemedicine applications have got a great potential to improve health care and reduce expenditures. Hence, this publication discusses offers, chances and the cost-effectiveness of telemedicine.  相似文献   
956.
High-quality science communication to the public depends to a large extent on the way research findings are translated into comprehensible language and common speech. In this communicative process, a reasonable evaluation of the trustworthiness of empirical findings, based on an adequate interpretation of statistical analyses, is absolutely crucial. This paper’s authors argue that the credibility of science is jeopardised by two compromising developments within science itself: on the one hand, an inflation of ostensible empirical evidence related to misuses and misinterpretations of the concept of statistical significance, and, on the other, a sensationalist overvaluation of the results of single studies instead of an adequate representation of the available body of evidence in a given scientific field.  相似文献   
957.
Many of the most active and most dangerous security challenges in the Asia-Pacific region are generally seen to involve a complex amalgam of material and ideational conflicts. There is surprisingly little consideration, however, of the role of the justice motive. This article explores the role of the justice motive in the context of three specific maritime and territorial disputes: Dokdo/Takeshima, the Senkaku/Diaoyu Islands, and the South China Sea. What explains its intensity? How does it affect political salience, tractability, and danger of conflict? What are the available mechanisms and prospects for resolving justice conflicts?  相似文献   
958.
959.
Informal Traders and the Battlegrounds of Revanchism in Cusco,Peru   总被引:2,自引:0,他引:2  
Informal trading in the global South, particularly in Latin America, is the subject of revanchist urban policy and yet few studies have examined the longer‐term impacts of such intolerant policies on traders. This article explores the evolution and impacts of revanchist policies directed at informal traders in the Andean city of Cusco. It makes two key contributions. First, it documents a shift from early revanchist policies to a post‐revanchist era where policies have become more tolerant of informal traders. However, contemporary policies fall short of a supportive environment for informal trading, hence the authors recommend changes that will ensure informal traders can access the city's streets and become an accepted part of the urban fabric. Second, given the lack of theoretical attention given to the impacts of revanchism, a battlegrounds framework is developed, consisting of spatial, political, economic and socio‐cultural battlegrounds. This framework provides a comprehensive insight into the complex set of interactions that exist between informal traders and the state. It is hoped that the framework will provide a tool for further research into the highly damaging impacts of revanchism across the globe.  相似文献   
960.
We extend the Rothschild-Stiglitz (RS) insurance market model with adverse selection by allowing insurers to offer either non-participating or participating policies, that is, insurance contracts with policy dividends or supplementary calls for premium. It is shown that an equilibrium always exists in such a setting. Participating policies act as an implicit threat that dissuades deviant insurers who aim to attract low-risk individuals only. The model predicts that the mutual corporate form should be prevalent in insurance markets where second-best Pareto efficiency requires cross-subsidisation between risk types.  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