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   17041篇
  免费   338篇
  国内免费   1篇
财政金融   3629篇
工业经济   1278篇
计划管理   2853篇
经济学   3784篇
综合类   213篇
运输经济   72篇
旅游经济   241篇
贸易经济   2609篇
农业经济   858篇
经济概况   1760篇
邮电经济   83篇
  2020年   177篇
  2019年   247篇
  2018年   276篇
  2017年   316篇
  2016年   311篇
  2015年   214篇
  2014年   333篇
  2013年   1568篇
  2012年   412篇
  2011年   438篇
  2010年   393篇
  2009年   455篇
  2008年   406篇
  2007年   417篇
  2006年   369篇
  2005年   345篇
  2004年   318篇
  2003年   363篇
  2002年   328篇
  2001年   338篇
  2000年   376篇
  1999年   308篇
  1998年   322篇
  1997年   334篇
  1996年   324篇
  1995年   317篇
  1994年   318篇
  1993年   309篇
  1992年   342篇
  1991年   363篇
  1990年   291篇
  1989年   229篇
  1988年   245篇
  1987年   232篇
  1986年   271篇
  1985年   369篇
  1984年   349篇
  1983年   307篇
  1982年   317篇
  1981年   349篇
  1980年   292篇
  1979年   300篇
  1978年   265篇
  1977年   194篇
  1976年   194篇
  1975年   198篇
  1974年   151篇
  1973年   172篇
  1972年   126篇
  1971年   107篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Farley discusses progress US blacks have made in the areas of voting and citizenship rights, residency and housing, and education. A major goal of the civil rights movement was to permit blacks to influence the electoral process in the same manner as whites. Most important in this regard was the Voting Rights Act of 1965; the proportion of southern blacks casting ballots increased sharply since the early 1960s. The Civil Rights Act of 1875 outlawed racial segregation in public accommodations, but by the turn of the century, Jim Crow laws in southern states called for segregation in most public places. Common customs and government policy in the North resulted in similar segregation of blacks from whites. The Montgomery bus boycott and similar protests in dozens of other cities led to enactment of Title II of the Civil Rights Act of 1964, which proscribed such racial practices. By the late 1960s, blacks in all regions could use the same public accommodations as whites. In most metropolitan areas, de facto racial segregation persisted long after the laws were changed. Supreme Court decisions and local open-housing ordinances supported the right of blacks to live where they could afford. However the major change was the Fair Housing Act of 1968, which outlawed racial discrimination in the sale or rental of most housing units. The separation of blacks from whites did not end in the 1970s. Today, in areas which have large black populations, there are many central city neighborhoods and a few in the suburbs which are either all-black or are becoming exclusively black enclaves. Most other neighborhoods have no more than token black populations. Another major effort of civil rights organizations has been the upgrading of housing quality for blacks. By 1980, only 6% of the homes and apartments occupied by blacks lacked complete plumbing facilities (down from 50% in 1940). Unlike the modest changes in residential segregation, racial differences in housing quality have been greatly reduced. By 1960, black students approached parity with whites in terms of measurable aspects of school facilities. In 1940, young blacks averaged about 3 fewer years of educational attainment than whites; the time is nearing when the years of schooling completed by blacks and whites will be the same. In small and medium-sized cities throughout the country, public schools are generally integrated. However, the situation in the largest metropolitan areas is very different. Today, large public schools are segregated, in large part, because blacks and whites live in separate school districts.  相似文献   
82.
The main results of eleven studies of the nature and determinants of the timing of moves and duration of residence effects are presented. The studies (see table 1) illustrate the use of the methodological framework for studying individual histories of the previous article. There are substantial duration of residence effects in most population subgroups, implying that the migration process in non-Markovian at the mocro level and that the semi-Markov model is required. However, characterization of effects and their determinants are shown to depend so heavily on the type of interval and observation scheme used, that only within a comprehensive framework is proper interpretation of empirical results possible.  相似文献   
83.
There is some debate about the potential value of using devil's advocates in top-level organizational decision-making. In this paper, the contrasting views on this question are summarized briefly and the field and laboratory research on the devil's advocate and related techniques is discussed. This research is then used as the basis for detailed suggestions on the effective use of devil's advocates in improving managerial decisions.  相似文献   
84.
It is shown that minimum distance estimators for families of unimodal densities are always consistent; the rate of convergence is indicated. An algorithm is proposed for computing the minimum distance estimator for the family of all unimodal densities. References are given to the maximum likelihood method and the kernel method.  相似文献   
85.
The simulation problem is one of the most commonly used formats in computer-assisted instruction (CAI). In medical education, a patient simulation problem is known as a patient management problem (PMP). A number of computerized PMP systems are currently available. However, to date, there is no record of PMP systems having been developed using artificial intelligence. This is noteworthy since artificial intelligence techniques could help in the generation of more effective and intelligent instructional systems.

This paper analyzes and evaluates existing instructional simulation software in clinical medicine in terms of effective educational design attributes. Components of effective PMP systems thus identified are incorporated into a computerized instructional system which uses artificial intelligence techniques for teaching problem-solving and diagnostic skills to undergraduate medical students.  相似文献   

86.
Summary In this paper it is investigated whether robust estimation procedures for the parameters of a regression model are also applicable when the observations are generated by the errors-in-variables model. Specifically, attention is paid to bounded-influence estimators, i.e. estimators that are constructed in such a way that the influence of a single observation on the outcome of the estimator is bounded. Both the classical errors-in-variables model and models with contaminated observational errors are considered.The authors are indebted to a referee for his valuable comments on an earlier version of this paper.  相似文献   
87.
A bstract . Developing countries have called for the establishment of a new International Economic Order. New perceptions of development are examined as they relate to haste needs and the transfer of technology within such a framework. The approach seeks to reduce and eventually to eliminate dependence on developed country enterprises, thus allowing developing countries to control their natural resources. It seeks to accelerate self-reliance and to introduce some measure of global management of resources. Technology transferred must be appropriate technology, adapted to local conditions and aimed at meeting specific local needs.  相似文献   
88.
Abstract. In this paper we study the first–order efficiency and asymptotic normality of the maximum likelihood estimator obtained from dependent observations. Our conditions are weaker than usual, in that we do not require convergences in probability to be uniform or third–order derivatives to exist.
The paper builds on Witting and Nolle's result concerning the asymptotic normality of the maximum likelihood estimator obtained from independent and identically distributed observations, and on a martingale theorem by McLeish.  相似文献   
89.
Summary So far, the labour market has not received any special attention from macro-econometric model builders. In this article an attempt has been made to describe the labour market in detail, paying attention to such important phenomena as the friction between labour supply and demand, the heterogeneity of labour, the dependence of labour supply on the labour-market situation, the Phillips mechanism and the impact of real wages on labour demand. To make it suitable for policy simulations, the model has been extended to a complete macro-econometric model, taking account of the fact that both labour and capital limit the production possibilities.This paper summarises an extensive Dutch report on the construction of a model for the Netherlands labour market. The title of the original report is AMO-K: Een arbeidsmarktmodel met twee categorieën arbeid; (AMO-K, A labour-market model with two categories of labour) ; it was published by the Netherlands Economic Institute (NEI) in Rotterdam in the so-called Olive Series, 1982-2, pp. 403ff. Some details of the model presented in that report were changed after its publication; see G. den Broeder, AMO-K 81-12, Tussenrapport betreffende de verdere ontwikkeling van het arbeidsmarktmodel (Interim report on the further development of the labourmarket model), Rotterdam, September 1983. Since then, only minor changes have been carried through. The model reproduced in this paper is the modified version. The model was developed within the National Programme of Labour-Market Research (NPAO) (now defunct), the NPAO organisation having granted a commission to the NEI in Rotterdam.  相似文献   
90.
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