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   25452篇
  免费   567篇
  国内免费   14篇
财政金融   4595篇
工业经济   2079篇
计划管理   4258篇
经济学   5448篇
综合类   457篇
运输经济   178篇
旅游经济   445篇
贸易经济   4470篇
农业经济   1347篇
经济概况   2727篇
信息产业经济   1篇
邮电经济   28篇
  2021年   150篇
  2020年   268篇
  2019年   375篇
  2018年   469篇
  2017年   516篇
  2016年   495篇
  2015年   346篇
  2014年   536篇
  2013年   2446篇
  2012年   696篇
  2011年   759篇
  2010年   697篇
  2009年   779篇
  2008年   739篇
  2007年   775篇
  2006年   634篇
  2005年   559篇
  2004年   540篇
  2003年   529篇
  2002年   539篇
  2001年   500篇
  2000年   524篇
  1999年   456篇
  1998年   471篇
  1997年   478篇
  1996年   460篇
  1995年   424篇
  1994年   423篇
  1993年   431篇
  1992年   467篇
  1991年   447篇
  1990年   381篇
  1989年   334篇
  1988年   286篇
  1987年   357篇
  1986年   356篇
  1985年   498篇
  1984年   522篇
  1983年   485篇
  1982年   437篇
  1981年   441篇
  1980年   389篇
  1979年   414篇
  1978年   292篇
  1977年   291篇
  1976年   231篇
  1975年   232篇
  1974年   193篇
  1973年   184篇
  1972年   133篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
When assessing farming strategies, it is important to account for the opportunities provided for tactically adjusting to outcomes of risk. The hypothesis that accounting for tactical adjustment is more important than accounting for risk attitude was supported in this study with regard to identifying the optimal drainage recirculation strategy for an irrigated dairy farm. Failing to account for tactical adjustment would lead to a sub-optimal choice, costing the farmer about A$3 100 in present value terms. In contrast, failing to account for risk aversion would not affect the strategy chosen. The distribution method was found to be well suited to modelling tactical adjustment.  相似文献   
73.
The Internet furore over Intel's flawed Pentium chip provides an important case study of the ethical ambiguity of internet communications and the legitimacy of certain forms of "electronic activism". Joseph Badaracco, Jr., is John Shad Professor of Business Ethics at the Harvard Business School and his co-author is a former Research Associate at Harvard and currently on the editorial staff of Inc . magazine.  相似文献   
74.
Supply chain management (SCM) is implemented by integrating corporate functions using business processes within and across companies. Several process‐oriented frameworks for SCM have been proposed but only two of these provide sufficient detail to enable implementation. We evaluate the Supply‐Chain Operations Reference (SCOR) framework and The Global Supply Chain Forum (GSCF) framework using four criteria and identify their relative strengths and weaknesses.  相似文献   
75.
Cash settlement of derivative contracts makes them susceptible to manipulation by traders who expect to close large positions upon final settlement. Cash settlement also increases underlying volatility when hedgers unwind their hedges if they have no incentives to control their trading costs. Limits on the positions that traders can carry into final settlement can be used to mitigate associated economic inefficiencies when surveillance is insufficient. This article develops a model that regulators can use to set these limits that is based upon microstructure theory. The empirical findings indicate that existing position limits are largely inconsistent with those suggested by the model. © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:945–965, 2005  相似文献   
76.
"This study surveys the policy issues associated with urbanization following the abolition of the pass laws [in South Africa]. The demographic background is briefly sketched. Using neo-classical analysis as a starting point, particular attention is paid to the present inefficiencies of city form associated with segregation. It is argued that current planning procedures are in danger of perpetuating or even worsening the situation. Obstacles to employment generation are considered and transport, local government and housing issues are discussed. On every front, urbanization policy is unstable and, even in the short term, there will be pressures to change it."  相似文献   
77.
"A projection model based on a multivariate continuous state, stochastic process is presented. The model allows multiple time-varying covariates to be used so parameters can be estimated from time series information on health changes and mortality, and their interaction. Health changes are simulated by altering parameters controlling the age trajectory and diffusion of risk factor means, variances, and covariances....By increasing the information used in projections it may be possible to better (a) anticipate the state of health at extreme ages, (b) forecast changes in health at specific ages over time, (c) stimulate the effects of specific interventions, and (d) determine the sensitivity of outcomes to a range of interventions."  相似文献   
78.
The critical state of the hospital industry, as previously described, generates a difficult decision environment for the materiel manager and those in the purchasing function. The unique life- and death circumstances of hospitals impose a further onus on those who manage them. In the name of saving lives, they can find a convenient excuse to disregard all moral principles, forgetting the Socratic dictum "it is not enough that one lives, but that one lives well." Without the moral "right stuff," they can easily give in to the seductions of momentary gains and glory through ethical short-cuts. There is wisdom and consolation in the words that "nice guys may appear to finish last, but usually they're running in a different race." Studies have established a direct relationship between corporate excellence and ethical values. The reality of competition in the hospital industry dictates that the integration of ethics into the life of the organization should happen by design and not by accident. This is what is meant by strategy. If hospitals would strive for excellence to survive and grow, they should have a strategy with a mission statement that also embodies its moral values and moral agenda. Such an approach does not guarantee that an organization will become immune to moral contamination, but it does provide an antidote.  相似文献   
79.
The REF, C, and score are a means to give quantitative values for product performance. Other product variables defined as humidity control factor, shear control factor, differential temperature control factor, product life factor, and cost factor were not addressed as part of this study. Additional variables include delivery, maintenance, and warranties. These components can be added to the score in some weighted manner as they become clinically founded. Interface pressures and shears were not measured for beds that are gatched. Each product tested will have characteristics pertinent to its own design that must be addressed to minimize sacral and coccyx skin breakdown when subjects are in this posture because some pneumatic pads bottom out to give excessive sacral and coccyx pressure while others wrinkle when used in this position. This is of major concern when one considers that the coccyx is more susceptible to pressure than any other bony prominence. There may be some aversion to labeling support product performance because it will allow the purchaser to know what is being bought. This initial study indicates the feasibility of quantitating what all patients require: a valid interface support surface for each specific need. The user can be adequately informed before the purchase as to a product's merits without being influenced by the results of inadequate testing, referrals, or sales media influences. Although cushions, shoes, or other prosthetic/orthotic devices were not part of this study, it is appropriate to rate all these devices in a similar manner by simply comparing pressure relief attained to that desired, expressing the result as a percentage of the worst case, and then labeling the product accordingly. Those subjects with sensation can rate comfort as part of the overall score. For cushions, ischial tuberosity pressure relief can be expressed as a percentage of the maximum attainable relief. Metatarsal head relief during gait as well as during static testing can be measured, and claims can be made for shoes and sneakers. Where impact loads and shear forces are paramount, the score must comprise appropriate parameters. Similarly, amputee distal stump relief as a percentage of worst case could be specified by the fitter. Iliac crest relief as a percentage of worst case can also be specified by the fitter. In all instances the score is not a subjective rating but one that can be measured correctly. All body support products can be given an REF, C value, and score as well as other qualifying values where appropriate instrumentation and sufficient subject sampling is used.  相似文献   
80.
Richman LS 《Fortune》1992,126(3):34-40
Many more than ever face the crises of childhood: violence, drugs, bad schools, poverty, divorce, or two parents at work. And no one seems to care.  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