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   39705篇
  免费   790篇
  国内免费   1篇
财政金融   7518篇
工业经济   2934篇
计划管理   6672篇
经济学   8848篇
综合类   434篇
运输经济   281篇
旅游经济   655篇
贸易经济   6309篇
农业经济   1782篇
经济概况   4957篇
信息产业经济   1篇
邮电经济   105篇
  2021年   253篇
  2020年   417篇
  2019年   580篇
  2018年   767篇
  2017年   791篇
  2016年   745篇
  2015年   565篇
  2014年   850篇
  2013年   3975篇
  2012年   1145篇
  2011年   1226篇
  2010年   1019篇
  2009年   1187篇
  2008年   1164篇
  2007年   1026篇
  2006年   968篇
  2005年   911篇
  2004年   895篇
  2003年   870篇
  2002年   821篇
  2001年   825篇
  2000年   810篇
  1999年   700篇
  1998年   715篇
  1997年   691篇
  1996年   670篇
  1995年   587篇
  1994年   630篇
  1993年   645篇
  1992年   631篇
  1991年   665篇
  1990年   573篇
  1989年   481篇
  1988年   485篇
  1987年   487篇
  1986年   515篇
  1985年   725篇
  1984年   663篇
  1983年   691篇
  1982年   652篇
  1981年   550篇
  1980年   571篇
  1979年   559篇
  1978年   475篇
  1977年   455篇
  1976年   376篇
  1975年   362篇
  1974年   339篇
  1973年   305篇
  1972年   243篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
Employment,schooling and productivity growth   总被引:1,自引:1,他引:0  
Summary This paper presents an empirical analysis of labour demand and labour productivity growth in The Netherlands. Assuming an aggregate production function with as factors capital and 3 types of labour, distinguished by educational attainment, cost minimization leads to a set of 3 labour demand relations to be estimated on time series data. Using the estimates and the implied elasticities, aggregate labour productivity growth is decomposed into factor substitution, autonomous factors, labour time shortening, economies of scale, utilization rates and the increased educational level of the working population. The contributions of substitution, utilization rates and education appear to be substantial, notably in the seventies.

List of symbols

Variables a i Efficiency index of skill leveli - C production - h i working-time index for skill leveli - g i steady-state growth rate of skill leveli - K capital stock - L i employment volume of skill leveli - L i * desired level of labour skill leveli - p output price - p * desired output price - s i * long-run static labour shares in the production value - p k rental price of capital - P index of total factor productivity - P l index of labour productivity - u i utilization rate of skill leveli - u k utilization rate of capital - w i wage rate for skill leveli - y production volume - y yij Hicks partial elasticities of complementarity - i steady-state cost share of skill leveli - k Bk steady-state cost share of capital - f lf highest level price index in cost function nesting - g 4 intermediate level price index in cost function nesting - h 4 lowest level price index in cost function nesting - i steady-state relative wage share of skill leveli - ij Allen partial elasticities of substitution Parameters d i l adjustment speed of skill leveli - d p price adjustment speed - M mark-up on marginal costs - scale elasticity of production - i distribution parameter in cost function,i = 3, g - i distribution parameter in cost function,i = k, h - i distribution parameter in cost function,i =1, 2 - i autonomous labour productivity growth for skill leveli - i cost share of skill level in base year - f production cost index in base year - i hours elasticity in labour efficiency index - group elasticity of substitution betweenL 3 and (K, (L 1,L 2)) - g Og group elasticity of substitution betweenK and (L 1,L 2) - h 6h group elasticity of substitution betweenL 1 andL 2 We would like to thank B. Downey, G.M.M. Gelauff, A. Nieuwenhuis, J.M.M. Ritzen, J.C. Siebrand and an unknown referee for helpful comments on earlier drafts.  相似文献   
123.
124.
Assessing and acquiring technology does not have to be chaotic, driven solely by price, clinical preference, and emotion. With the tools available, it can be distilled to a process of organized common sense, which results in maximum flexibility for the user and allows materiel managers to procure the best, most cost-effective equipment for the hospital.  相似文献   
125.
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   
126.
127.
As older Americans take a close look at their assets, promote their interest in unlocking the wealth accumulation in their U.S. Saving Bond holdings. Use careful planning and advice when promoting this gift strategy.  相似文献   
128.
129.
130.
AIDS wars     
Kosterlitz J 《National journal》1992,24(30):1727-1732
At the Centers for Disease Control, director William L. Roper battles the deadly AIDS epidemic and other rising health hazards. But critics say political interference sets back the effort to stem AIDS.  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