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   7847篇
  免费   134篇
财政金融   670篇
工业经济   212篇
计划管理   612篇
经济学   812篇
综合类   43篇
运输经济   14篇
旅游经济   29篇
贸易经济   589篇
农业经济   180篇
经济概况   731篇
水利工程   4088篇
邮电经济   1篇
  2018年   228篇
  2017年   235篇
  2016年   205篇
  2015年   120篇
  2014年   185篇
  2013年   499篇
  2012年   243篇
  2011年   229篇
  2010年   187篇
  2009年   213篇
  2008年   207篇
  2007年   248篇
  2006年   201篇
  2005年   152篇
  2004年   181篇
  2003年   143篇
  2002年   131篇
  2001年   103篇
  2000年   126篇
  1999年   118篇
  1998年   137篇
  1997年   108篇
  1996年   124篇
  1995年   117篇
  1994年   120篇
  1993年   114篇
  1992年   131篇
  1991年   129篇
  1990年   125篇
  1989年   104篇
  1988年   107篇
  1987年   112篇
  1986年   114篇
  1985年   116篇
  1984年   110篇
  1983年   102篇
  1982年   103篇
  1981年   121篇
  1980年   120篇
  1979年   108篇
  1978年   136篇
  1977年   145篇
  1976年   142篇
  1975年   112篇
  1974年   119篇
  1973年   107篇
  1972年   94篇
  1971年   96篇
  1969年   92篇
  1968年   89篇
排序方式: 共有7981条查询结果,搜索用时 0 毫秒
41.
Estrogenic personal care products in a greywater reuse system.   总被引:1,自引:0,他引:1  
The occurrence and fate of parabens in a greywater system was assessed. The potential for removal of residual paraben concentrations in effluent greywater with chlorine dioxide was also investigated. The influent to the greywater plant was characterised by considerable variation, with concentrations from below the detection limit to 40 microg/L and the five commonly used parabens in consumer products were frequently detected. After the biological treatment only two paraben were detected with concentration from 65-120 ng/L. Chlorine dioxide treatment of the biologically treated effluent with dosages down to 0.75 mg/L resulted in more than 97% reduction of all parabens. Formation of the by-product chloroform was insignificant from the chlorine dioxide treatment.  相似文献   
42.
A major challenge for Indonesian economic policy makers is to avoid the recurrence of conditions that could trigger a new economic crisis. One of the important dimensions of this challenge will be to conduct fiscal policy in a way that is sustainable, given the level of interest rates and the rate of growth of the economy. This paper synthesises various approaches to the measurement of fiscal sustainability that have appeared in the economic literature, relates these measures to the fundamental concept of fiscal solvency, and applies the framework to Indonesia over the period 1991–2003. The domestic and foreign debt positions of the central government are treated separately, to capture the influence of exchange rate changes on the relative costs of domestic and foreign borrowing. The empirical analysis indicates that Indonesia has met the fiscal sustainability criterion in recent years, except when the rupiah has depreciated heavily.  相似文献   
43.
44.
Conclusion On the basis of the foregoing conditions about the design of hydraulic-fill dams and technology of their construction and also with consideration of the results of comparative calculations of the permeability of these dams, for the upper reservoirs of pumped-storage stations we can recommend dams which have reliable impervious elements, namely, a diaphragm, facing, or placed clay core.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 31–35, May, 1985.  相似文献   
45.
Optimal Operation of Reservoir Systems using Simulated Annealing   总被引:5,自引:0,他引:5  
A stochastic search technique, simulated annealing (SA), is used to optimize the operation of multiple reservoirs. Seminal application of annealing technique in general to multi-period, multiple-reservoir systems, along with problem representation and selection of different parameter values used in the annealing algorithm for specific cases is discussed. The search technique is improved with the help of heuristic rules, problem-specific information and concepts from the field of evolutionary algorithms. The technique is tested for application to a benchmark problem of four-reservoir system previously solved using a linear programming formulation and its ability to replicate the global optimum solution is examined. The technique is also applied to a system of four hydropower generating reservoirs in Manitoba, Canada, to derive optimal operating rules. A limited version of this problem is solved using a mixed integer nonlinear programming and results are compared with those obtained using SA. A better objective function value is obtained using simulated annealing than the value from a mixed integer non-linear programming model developed for the same problem. Results obtained from these applications suggest that simulated annealing can be used for obtaining near-optimal solutions for multi-period reservoir operation problems that are computationally intractable.  相似文献   
46.
Geosynthetic materials in the form of geomembranes, geotextiles, geonets, geomats, geocomposites, etc., are used widely in modern dam construction. The article describes structural elements of dams in which various types of geosynthetics are used and those functions which geosynthetics perform in these elements.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 10, pp. 50–54, October, 1992.  相似文献   
47.
Strategic partnerships are commonplace in today's global economy. Effective use of partnerships are viewed increasingly as an important issue facing small, growth-oriented firms. A key debate is how small firms should manage supplier partnerships. Contrasting the debate about the extent to which small firms are inertial versus adaptive, the impact of growth on value chain partnerships with suppliers was investigated. Data collected from 91 pharmaceutical-related firms is used to test the proposition that firm growth is related positively to maintaining or to expanding relationships with suppliers, not to terminating partnerships. The paper further posits that this relationship between firm growth and the amount purchased from a supplier is moderated by the perceived effectiveness of the value-chain partnerships such that when effectiveness is higher, the relationship between sales growth and the amount purchased from a value-chain partner is stronger. The propositions, which are tested with regression analysis, are supported partially.  相似文献   
48.
The Golden Rule is endorsed in oneform or another by most cultures and majorreligions and is still espoused byphilosophers, business ethicists, and popularbusiness authors. Because it also resonateswith undergraduate business majors, it can bean effective teaching tool. This paperdescribes a way of teaching the Golden Rulethrough a series of business-oriented examplesintended to bring out its strengths andweaknesses. The method described alsointroduces students to some basic moralreasoning skills and acquaints them with a widerange of moral issues that arise in business. Kant's Formula of Humanity is discussed in thefinal section as a principle that overcomes atleast some of the Golden Rule's defects.  相似文献   
49.
50.
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