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   769篇
  免费   33篇
财政金融   148篇
工业经济   57篇
计划管理   106篇
经济学   209篇
综合类   6篇
运输经济   10篇
旅游经济   21篇
贸易经济   101篇
农业经济   43篇
经济概况   101篇
  2023年   11篇
  2022年   7篇
  2021年   5篇
  2020年   8篇
  2019年   13篇
  2018年   16篇
  2017年   21篇
  2016年   17篇
  2015年   13篇
  2014年   24篇
  2013年   66篇
  2012年   30篇
  2011年   34篇
  2010年   34篇
  2009年   25篇
  2008年   33篇
  2007年   34篇
  2006年   29篇
  2005年   25篇
  2004年   24篇
  2003年   14篇
  2002年   19篇
  2001年   25篇
  2000年   16篇
  1999年   17篇
  1998年   19篇
  1997年   12篇
  1996年   22篇
  1995年   14篇
  1994年   11篇
  1993年   10篇
  1992年   10篇
  1991年   8篇
  1989年   4篇
  1988年   6篇
  1987年   9篇
  1986年   7篇
  1985年   13篇
  1984年   11篇
  1983年   9篇
  1982年   8篇
  1981年   7篇
  1980年   12篇
  1979年   11篇
  1978年   6篇
  1977年   6篇
  1976年   3篇
  1975年   3篇
  1973年   4篇
  1972年   6篇
排序方式: 共有802条查询结果,搜索用时 303 毫秒
31.
The evaluation of a nonsustained wide QRS tachycardia in a life insurance applicant's exercise test presents a special challenge to the medical director because of the unpredictable and potentially lethal nature of these arrhythmias. Ventricular tachycardia accounts for up to 80% of wide QRS tachycardias in unselected populations and more than 95% of cases with a prior myocardial infarction. Malignant ventricular arrhythmias usually occur in the presence of significant structural heart disease. In this setting, ventricular arrhythmias carry a high risk of sudden cardiac death. Less commonly, ventricular tachycardia occurs in hearts that appear normal. In many such cases, however, the heart is in fact not normal, but rather has less visible abnormalities including derangements of cardiac ion channels or structural proteins. In these individuals, ventricular arrhythmias also carry a high risk of sudden cardiac death. There are, however, some ventricular tachycardia syndromes which occur in normal hearts that have a more benign prognosis.  相似文献   
32.
The presence of unexpected Q waves in an applicant's electrocardiogram poses a diagnostic dilemma for the medical director. On the one hand, the Q waves may be the remnants of a previously unsuspected "silent" myocardial infarction. Conversely, unexpected Q waves may represent a normal or positional variant, or an important noncoronary type of heart disease. This case study illustrates some of the pitfalls in interpreting applicants' electrocardiograms containing Q waves in the inferior leads.  相似文献   
33.
Richard Abel argues that in the period from 1910, when the motionpicture "revolution" succeeded and the American film marketwas emancipated from French domination, to 1914, when foreignfilms were nearly eliminated from the U.S. market, the Americanfilm industry was characterized by widespread experimentationand innovation, especially in the areas of promotion practices,distribution strategies, content refinement, and audience development.Six chapters of Abel's Americanizing the Movies bring to theforeground the battle of  相似文献   
34.
Subjects update prior information simultaneously versus sequentially. The mean prediction is remarkably close to the correct Bayesian estimate with simultaneous information, but differs significantly conditional on whether good news precedes bad news or vice versa.  相似文献   
35.
We investigate the economic feasibility of bioelectricity production from biomass in Malaysia and its impact on greenhouse gas (GHG) emissions and storage, agricultural prices, agricultural employment and deforestation. For this purpose, we develop a partial equilibrium model that projects agricultural prices, production, imports, exports, domestic consumption and land use in 5‐year increments between 2015 and 2065. Our results show that by 2030 biomass‐generated electricity can supply 36.5 per cent of the electricity generated in Malaysia, 16 times more than the 2016 electricity supply from biomass. Increased bioelectricity production from biomass will significantly reduce GHG emissions and will help Malaysia meet its commitment in the Paris Agreement to mitigate GHG emission by 45 per cent before 2030. Our modelling shows that biomass‐generated electricity creates a derived demand for waste biomass that expands the area of oil palm plantations. The expansion lowers agricultural prices, boosts agricultural employment and leads to some deforestation as landowners clear rainforest to plant oil palm trees. Nonetheless, the deforestation does not increase GHG emissions since GHG gains from bioelectricity significantly exceed GHG losses from deforestation.  相似文献   
36.
37.
Transient processes important to understanding technical change are modeled using a time-varying version of the Sequential Interindustry Model, SIM. A simple process of technical change is explored, where a new production technique replaces an old one for one of an industry's production processes. Using several measures internal and external to the industry the model can help in understanding the complex processes of technical change, point to difficulties in their analysis, and suggest guidance to further examinations. An earlier version of this paper was presented at the Eighth International Conference on Input-Output Techniques, Sapporo, Japan, July 1986.  相似文献   
38.
The concept of entrepreneurial ecosystems has quickly established itself as one of the latest ‘fads’ in entrepreneurship research. At face value, this kind of systemic approach to entrepreneurship offers a new and distinctive path for scholars and policy makers to help understand and foster growth-oriented entrepreneurship. However, its lack of specification and conceptual limitations has undoubtedly hindered our understanding of these complex organisms. Indeed, the rapid adoption of the concept has tended to overlook the heterogeneous nature of ecosystems. This paper provides a critical review and conceptualisation of the ecosystems concept: it unpacks the dynamics of the concept; outlines its theoretical limitations; measurement approaches and use in policy-making. It sets out a preliminary taxonomy of different archetypal ecosystems. The paper concludes that entrepreneurial ecosystems are a highly variegated, multi-actor and multi-scalar phenomenon, requiring bespoke policy interventions.  相似文献   
39.
This is one of the first studies to explore customer retention in reference to the franchisee–customer relationship. A subsequent objective was to examine localization and standardization from a franchise unit and system-level perspective. Data was collected using a self-administered survey based on customers of pet grooming services in Australia. Findings suggest that the addition of a customer retention perspective reveals a greater depth to the franchisee–customer relationship. Importantly, this implies that there are additional factors likely to influence franchisee–customer retention within franchise outlets. We suggest that individual franchise units, in cooperation with local customers, should co-create local marketing initiatives.  相似文献   
40.
The complexity of modern farm management places great demands on the skill, knowledge and capability of farm managers and their families. Keeping abreast of emerging technologies and innovations that can affect each key farm enterprise, and knowing how best to marshal the resources required for profitable farm production, are key tasks of farm management. This study draws on a longitudinal data set of 240 broadacre farmers to compare and analyse their farm performance over a decade. Using structural equation modelling, we examine relationships between the farm family's involvement in training, their human capital, their use of various innovations and ultimately the linkages of these factors to farm financial and productivity performance. Several statistically significant inter‐relationships are found, and some factors are shown to have significant positive links to farm performance. We find that training undertaken by the farm family, the farm family's human capital and their use of innovations, particularly key cropping innovations, have significant beneficial impacts on farm performance. The farmer's skills in time and organisational management, their engagement in business planning and the unique environmental characteristics of the farm also significantly and positively influence farm performance.  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