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   10828篇
  免费   311篇
  国内免费   2篇
管理学   1499篇
民族学   64篇
人才学   3篇
人口学   971篇
丛书文集   71篇
理论方法论   1108篇
综合类   228篇
社会学   5606篇
统计学   1591篇
  2020年   155篇
  2019年   249篇
  2018年   265篇
  2017年   379篇
  2016年   263篇
  2015年   200篇
  2014年   260篇
  2013年   1770篇
  2012年   356篇
  2011年   351篇
  2010年   282篇
  2009年   262篇
  2008年   258篇
  2007年   301篇
  2006年   267篇
  2005年   268篇
  2004年   246篇
  2003年   182篇
  2002年   215篇
  2001年   277篇
  2000年   233篇
  1999年   216篇
  1998年   170篇
  1997年   162篇
  1996年   157篇
  1995年   146篇
  1994年   152篇
  1993年   150篇
  1992年   152篇
  1991年   149篇
  1990年   156篇
  1989年   152篇
  1988年   134篇
  1987年   148篇
  1986年   119篇
  1985年   149篇
  1984年   157篇
  1983年   144篇
  1982年   124篇
  1981年   90篇
  1980年   113篇
  1979年   116篇
  1978年   102篇
  1977年   86篇
  1976年   88篇
  1975年   100篇
  1974年   94篇
  1973年   71篇
  1972年   61篇
  1971年   53篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
62.
63.
In 2002, the European Union changed direction from its past efforts to harmonise European accounting systems and turned instead to a subcontractor, requiring listed European companies to adopt accounting standards drawn up by a private London-based organisation, the IASB (International Accounting Standards Board), which had until then had no public mandate. This decision was all the more significant because the EU has no institutional means of control over the IASB, although it was the first geographical group to decide to impose these standards on its businesses. IASB standards are rooted in the “anglo-saxon” tradition of standardisation for the financial markets, and the view of the enterprise they promote diverges from the accounting traditions of continental European capitalism. This article shows how the new standards are transforming the concept of enterprise, and examines the span of factors that brought about what is a major institutional change for European capitalism. — Special issue: New patterns of institutions.  相似文献   
64.
While most of epidemiology is observational, rather than experimental, the culture of epidemiology is still derived from agricultural experiments, rather than other observational fields, such as astronomy or economics. The mismatch is made greater as focus has turned to continue risk factors, multifactorial outcomes, and outcomes with large variation unexplainable by available risk factors. The analysis of such data is often viewed as hypothesis testing with statistical control replacing randomization. However, such approaches often test restricted forms of the hypothesis being investigated, such as the hypothesis of a linear association, when there is no prior empirical or theoretical reason to believe that if an association exists, it is linear. In combination with the large nonstochastic sources of error in such observational studies, this suggests the more flexible alternative of exploring the association. Conclusions on the possible causal nature of any discovered association will rest on the coherence and consistency of multiple studies. Nonparametric smoothing in general, and generalized additive models in particular, represent an attractive approach to such problems. This is illustrated using data examining the relationship between particulate air pollution and daily mortality in Birmingham, Alabama; between particulate air pollution, ozone, and SO2 and daily hospital admissions for respiratory illness in Philadelphia; and between ozone and particulate air pollution and coughing episodes in children in six eastern U.S. cities. The results indicate that airborne particles and ozone are associated with adverse health outcomes at very low concentrations, and that there are likely no thresholds for these relationships.  相似文献   
65.
66.
67.
Rainfall interception by Santa Monica's municipal urban forest   总被引:4,自引:2,他引:2  
Effects of urban forests on rainfall interception and runoff reduction have been conceptualized, but not well quantified. In this study rainfall interception by street and park trees in Santa Monica, California is simulated. A mass and energy balance rainfall interception model is used to simulate rainfall interception processes (e.g., gross precipitation, free throughfall, canopy drip, stemflow, and evaporation). Annual rainfall interception by the 29,299 street and park trees was 193,168 m3 (6.6 m3/tree), or 1.6% of total precipitation. The annual value of avoided stormwater treatment and flood control costs associated with reduced runoff was $110,890 ($3.60/tree). Interception rate varied with tree species and sizes. Rainfall interception ranged from 15.3% (0.8 m3/tree) for a small Jacaranda mimosifolia (3.5 cm diameter at breast height) to 66.5% (20.8 m3/tree) for a mature Tristania conferta (38.1 cm). In a 25-year storm, interception by all street and park trees was 12,139.5 m3 (0.4%), each tree yielding $0.60 (0.4 m3/tree) in avoided flood control costs. Rainfall interception varied seasonally, averaging 14.8% during a 21.7 mm winter storm and 79.5% during a 20.3 mm summer storm for a large, deciduous Platanus acerifolia tree. Effects of differences in temporal precipitation patterns, tree population traits, and pruning practices on interception in Santa Monica, Modesto, and Sacramento, California are described.  相似文献   
68.
69.
Sources of drug information among adolescent students   总被引:1,自引:0,他引:1  
A sample of 1023 eighth and tenth grade students in small to medium-sized central Texas school districts was assessed to determine the amount of information they receive from ten sources about six categories of drugs. The amount of information males reported receiving about each drug category was significantly greater than what females reported, and the amount of information that eighth graders reported receiving about each drug category was significantly greater than what tenth graders reported. Television was the primary source of drug information for all categories of drugs except inhalants, for which friends and television were equally important sources. Parents and printed media (magazines or newspapers) were of secondary importance, followed by friends and teachers. Adolescents were less likely to receive drug-related information from experience, siblings, church, doctors, and police. The reliance on the mass media for drug information in smaller school districts is a pattern which has been previously observed in larger urban districts. This consistency suggests that mass media approaches to drug education are likely to be as effective in rural areas and smaller towns as they are among urban adolescents. Implications for television programming are discussed.  相似文献   
70.
This study investigates the extent and nature of housing affordability for elderly nonmetropolitan female heads of household using data from the Panel Study of Income Dynamics. The results indicate that over one-third of elderly nonmetropolitan female heads of household experience housing poverty and that those who rent, who have fair to poor health, and who are minorities are particularly vulnerable. Housing affordability, measured by the concept of housing poverty, identifies households struggling to meet basic needs while the conventional 25% of income for housing expenditures ratio identifies a larger population. The findings suggest the need for multifaceted public policies to address the problem of housing poverty. Her research interests include housing affordability, housing and community vitality, and decision making. She received her Ph.D. from Purdue University. Sooyoun Park is in the same department as a Project Assistant on a USDA-funded research project entitled “Housing Affordability in Rural Areas,” which is a joint project between Nebraska and Wisconsin. Her research interests focus on housing management behavior in relation to housing expenditure burden. She received her Ph.D. from the University of Nebraska-Lincoln.  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