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   29607篇
  免费   282篇
财政金融   5085篇
工业经济   1808篇
计划管理   4518篇
经济学   6653篇
综合类   641篇
运输经济   92篇
旅游经济   183篇
贸易经济   6379篇
农业经济   739篇
经济概况   3164篇
信息产业经济   46篇
邮电经济   581篇
  2020年   124篇
  2019年   168篇
  2018年   2456篇
  2017年   2213篇
  2016年   1381篇
  2015年   232篇
  2014年   269篇
  2013年   1306篇
  2012年   706篇
  2011年   2238篇
  2010年   2086篇
  2009年   1827篇
  2008年   1806篇
  2007年   2103篇
  2006年   335篇
  2005年   674篇
  2004年   717篇
  2003年   834篇
  2002年   476篇
  2001年   327篇
  2000年   311篇
  1999年   250篇
  1998年   259篇
  1997年   253篇
  1996年   282篇
  1995年   251篇
  1994年   232篇
  1993年   203篇
  1992年   230篇
  1991年   239篇
  1990年   215篇
  1989年   178篇
  1988年   178篇
  1987年   144篇
  1986年   213篇
  1985年   272篇
  1984年   265篇
  1983年   264篇
  1982年   229篇
  1981年   237篇
  1980年   209篇
  1979年   223篇
  1978年   196篇
  1977年   166篇
  1976年   144篇
  1975年   138篇
  1974年   132篇
  1973年   104篇
  1972年   102篇
  1971年   93篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
991.
The authors argue that it is possible to partly automate the process of abstract control of fairness of clauses in online consumer contracts. The authors present a theoretical and empirical argument for this claim, including a brief presentation of the software they have designed. This type of automation would not replace human lawyers but would assist them and make their work more effective and efficient. Policy makers should direct their attention to the potential of using algorithmic techniques in enforcing the law regarding unfair contractual terms, and to facilitating research on and ultimately implementing such technologies.  相似文献   
992.
Peixin Zhao  Liugen Xue 《Metrika》2011,74(2):231-245
This paper focuses on variable selections for varying coefficient models when some covariates are measured with errors. We present a bias-corrected variable selection procedure by combining basis function approximations with shrinkage estimations. With appropriate selection of the tuning parameters, we establish the consistency of the variable selection procedure, and derive the optimal convergence rate of the regularized estimators. A simulation study and a real data application are undertaken to assess the finite sample performance of the proposed variable selection procedure.  相似文献   
993.
Scientific collaboration is a complex phenomenon that improves the sharing of competences and the production of new scientific knowledge. Social Network Analysis is often used to describe the scientific collaboration patterns defined by co-authorship relationships. Different phases of the analysis of collaboration are related to: data collection, network boundary setting, relational data matrix definition, data analysis and interpretation of results. The aim of this paper is to point out some issues that arise in these different phases, highlighting: (i) the use of local archives versus international bibliographic databases; (ii) the use of different approaches for setting boundaries in a whole-network; (iii) the definition of a co-authorship data matrix (binary and weighted ties) and (iv) the analysis and the interpretation of network measures for co-authorship data. We discuss the different choices that can be made in these phases within an illustrative example on real data which is referred to scientific collaboration among researchers affiliated to an academic institution. In particular, we compare global and actor-level network measures computed from binary and weighted co-authorship networks in different disciplines.  相似文献   
994.
995.
There is a broad literature linking social support to health, which includes evidence that social support from supervisors is positively associated with worker health. In addition, once workers experience a health concern, supervisors may play a key role in supporting workers, keeping them on the job despite health issues. However, there are few studies that investigate the day-to-day strategies supervisors utilize to support their workers and help them stay on the job despite health concerns. The study presented in this paper addresses this gap. Thirty-two supervisors from three companies were interviewed about their experiences supporting and accommodating skilled workers during flare-ups of a health condition. A grounded theory approach was used to analyze the text data and identify themes. Three key themes emerged from the data: 1) workplace policies provide the structure for mutual problem solving; 2) communication skills and existing relationships increase supervisor effectiveness; and 3) strategies were aimed at individual, interpersonal, and institutional supports. Supervisors regularly interact with workers to support and accommodate episodes of illness or pain. While supervisors employ novel and effective strategies, there is an opportunity to improve the range of strategies, better understand and utilize company policies, and facilitate appropriate communication about worker health concerns.  相似文献   
996.
The current study examines the relationship between adult attachment style and both perceived psychological contract breach and affective organizational commitment in a sample of college students with employment experience. Attachment style is argued to be an individual difference factor that affects how an individual perceives organizational events based on theory and existing empirical research related to adult attachment style. Individuals with insecure attachment styles were predicted to perceive more psychological contract breach and have lower levels of affective organizational commitment. The results reveal that individuals with higher levels of preoccupied and dismissive attachment styles perceived higher levels of psychological contract breach, and preoccupied attachment style significantly and negatively relates to affective organizational commitment. The relationship between attachment style and psychological contract dimensions was stronger for relational than transactional contract dimensions. Evidence is also found that perceived psychological contract breach mediates the relationship between preoccupied attachment style and affective commitment. Future potential research directions are described. The implications of these findings for managerial practice is discussed.  相似文献   
997.
This research explores the effects of securitization on the market’s perception of banks’ risk exposure between 2002 and 2007. Our results show that, contrary to some prior evidence in the literature, securitizing banks actually had lower systematic betas until 2007. We find no evidence of increasing idiosyncratic risk with securitization. We identify significant structural break in 2007, when securitizing banks experienced jumps in both systematic and idiosyncratic risks. Finally, we confirm the general belief that larger banks tend to have higher systematic risk and lower idiosyncratic risk because of diversification.  相似文献   
998.
We reveal an interesting convex duality relationship between two problems: (a) minimizing the probability of lifetime ruin when the rate of consumption is stochastic and the individual can invest in a Black–Scholes financial market; (b) a controller-and-stopper problem, in which the controller controls the drift and volatility of a process in order to maximize a running reward based on that process, and the stopper chooses the time to stop the running reward and pays the controller a final amount at that time. Our primary goal is to show that the minimal probability of ruin, whose stochastic representation does not have a classical form as does the utility maximization problem (i.e., the objective’s dependence on the initial values of the state variables is implicit), is the unique classical solution of its Hamilton–Jacobi–Bellman (HJB) equation, which is a non-linear boundary-value problem. We establish our goal by exploiting the convex duality relationship between (a) and (b).  相似文献   
999.
We prove that, under very weak conditions, optimal financial products on complete markets are co-monotone with the reversed state price density. Optimality is meant in the sense of the maximization of an arbitrary preference model, e.g., expected utility theory or prospect theory. The proof is based on a result from transport theory. We apply the general result to specific situations, in particular the case of a market described by the Capital Asset Pricing Model or the Black–Scholes model, where we derive a generalization of the two-fund-separation theorem and give an extension to APT factor models and structured products with several underlyings. We use our results to derive a new approach to optimization in wealth management, based on a direct optimization of the return distribution of the portfolio. In particular, we show that optimal products can (essentially) be written as monotonic functions of the market return. We provide existence and nonexistence results for optimal products in this framework. Finally we apply our results to the study of bonus certificates, show that they are not optimal, and construct a cheaper product yielding the same return distribution.  相似文献   
1000.
Creativity is acknowledged to be important for economic growth and as an everyday life-skill, however several influential reports have suggested that education could do more to harness creative talent. Creative cognition literature suggests the lack of creativity is at least partly the result of ‘fixation’ (difficulty in generating novel ideas due to imagination being ‘structured’ by existing knowledge). This paper focuses on the secondary (students aged 11–16 years) design and technology (D&T) context in the UK. Here we examine whether teacher practice can contribute to fixation by focusing on one specific facet of teacher practice in D&T; the use of product analysis to inform the generation of creative design ideas. Data is drawn from the preliminary phase of a research and intervention project from interviews with D&T teachers (N = 14), students (N = 126) and lesson observations (N = 10) and an analysis of documents and student work. Product analysis is widely used at different points in design projects but, as is shown, in all cases current practice can lead to fixation, as thinking is constrained down specific paths and tasks are at best at procedural rather than comprehension level. The implications of these findings and tentative ways forward for practitioners are discussed.  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