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   5250篇
  免费   204篇
管理学   943篇
民族学   41篇
人才学   1篇
人口学   410篇
丛书文集   24篇
教育普及   1篇
理论方法论   621篇
综合类   70篇
社会学   2687篇
统计学   656篇
  2023年   47篇
  2022年   27篇
  2021年   37篇
  2020年   105篇
  2019年   166篇
  2018年   150篇
  2017年   230篇
  2016年   161篇
  2015年   146篇
  2014年   157篇
  2013年   861篇
  2012年   212篇
  2011年   254篇
  2010年   169篇
  2009年   148篇
  2008年   162篇
  2007年   194篇
  2006年   173篇
  2005年   169篇
  2004年   164篇
  2003年   129篇
  2002年   153篇
  2001年   126篇
  2000年   100篇
  1999年   96篇
  1998年   71篇
  1997年   69篇
  1996年   55篇
  1995年   53篇
  1994年   45篇
  1993年   64篇
  1992年   55篇
  1991年   51篇
  1990年   52篇
  1989年   55篇
  1988年   50篇
  1987年   38篇
  1986年   42篇
  1985年   30篇
  1984年   51篇
  1983年   39篇
  1982年   42篇
  1981年   40篇
  1980年   37篇
  1979年   32篇
  1978年   28篇
  1977年   19篇
  1976年   21篇
  1975年   20篇
  1974年   14篇
排序方式: 共有5454条查询结果,搜索用时 578 毫秒
141.
In this paper we compare several types of economic dependency ratios for a selection of European countries. These dependency ratios take into account not only the demographic structure of the population, but also the differences in age-specific economic behaviour such as labour market activity, income and consumption as well as age-specific public transfers. In selected simulations where we combine patterns of age-specific economic behaviour and transfers with population projections, we show that in all countries population ageing would lead to a pronounced increase in dependency ratios if present age-specific patterns were not to change. Our analysis of cross-country differences in economic dependency demonstrates that these differences are driven by both differences in age-specific economic behaviour and in the age composition of the populations. The choice of which dependency ratio to use in a specific policy context is determined by the nature of the question to be answered. The comparison of our various dependency ratios across countries gives insights into which strategies might be effective in mitigating the expected increase in economic dependency due to demographic change.  相似文献   
142.
The internet and other digital networks in the U.S. (and beyond) remain essentially an upgrade of the national telephone network built by AT&T over the first half of the twentieth century, and digital payment remains tethered to telephony at the level of infrastructure. Telephone history also continues to inform digital payment at the level of interface. Debit card readers feature a keypad nearly identical to those introduced (also by AT&T) to the dialling public a half-century ago on touch-tone telephones. In this essay I highlight the development of the touch-tone keypad as a transformative payment technology. There have been three great leaps forward in the history of telephone interface: the dial, the keypad and the touch screen. Each corresponds to a period of technological transformation in the telephone industry and society more broadly: the rotary dial and automation, touch-tone keypads and digitization, and touch screens and computerization. The successful careers of the dial and the keypad, especially when read in tandem, suggest that touch screens will alter the everyday economics of retail payment even more radically than its predecessors. I also describe a broader trajectory of digital naturalization, whereby telephone numbers have proliferated into a personal identification number, passwords and a plethora of personalized information. Payments increasingly circulate today as subsets of personal information within the vast sea of big data. Payment apps are demonstrating a capacity to reorganize retail transactions on a scale as vast as any technology since the cash register. The history of retail payment finds the point of sale heading from the till into shoppers’ pockets. As a result, consumers are increasingly shouldering the costs of purchasing, maintaining, upgrading and securing the technology used for everyday transactions.  相似文献   
143.
In this article, I explore the intricate relationship between regulation and contingency in processes of urban economic organisation by focusing on the workings of a central bus station in Accra, Ghana. After introducing the position of the station in Ghana’s urban economy and transport infrastructure, I set out its internal regulative arrangements in relation to larger socio-economic and political constellations the practices of the station workers are contingent upon. Next, I turn the analysis around and describe the ways in which people accommodate themselves within, exploit and thereby co-produce emergent contingencies. The focus on the station, I suggest, offers a window into the complex constituents of niche economic practices that prevail in many spheres of African cities and allows a nuanced reflection on the incongruous and undetermined dynamics of everyday urban ‘becomings.’  相似文献   
144.
Urban growth is a major factor of global environmental change and has important impacts on biodiversity, such as changes in species composition and biotic homogenization. Most previous studies have focused on effects of urban area as a general measure of urbanization, and on few or single taxa. Here, we analyzed the impacts of the different components of urban sprawl (i.e., scattered and widespread urban growth) on species richness of a variety of taxonomic groups covering mosses, vascular plants, gastropods, butterflies, and birds at the habitat and landscape scales. Besides urban area, we considered the average age, imperviousness, and dispersion degree of urban area, along with human population density, to disentangle the effects of the different components of urban sprawl on biodiversity. The study was carried out in the Swiss Plateau that has undergone substantial urban sprawl in recent decades.Vascular plants and birds showed the strongest responses to urban sprawl, especially at the landscape scale, with non-native and ruderal plants proliferating and common generalist birds increasing at the expense of specialist birds as urban sprawl grew. Overall, urban area had the greatest contribution on such impacts, but additional effects of urban dispersion (i.e., increase of non-native plants) and human population density (i.e., increases of ruderal plants and common generalist birds) were found. Our findings support the hypothesis that negative impacts of urban sprawl on biodiversity can be reduced by compacting urban growth while still avoiding the formation of very densely populated areas.  相似文献   
145.
BackgroundSevere perineal tears sustained during childbirth cause significant distress and morbidity amongst women. The objective of this study was to compare the use of straight scissors for cutting an episiotomy with the use of curved scissors, which are designed to curve away from the anal sphincter.MethodsWe used a single-centre, randomised feasibility trial. The intervention was the use of curved scissors. Women were recruited during a prenatal visit and randomised in the delivery suite, when it became clear that an episiotomy was required. The feasibility outcomes were the proportion of women able to be recruited, randomised and followed up. We also calculated the incidence of obstetric anal sphincter injury when either straight or curved scissors were used to cut an episiotomy. Other outcomes assessed were pain, length of hospital stay, perineal infection and perineal dehiscence.ResultsOf the 155 patients recruited in the prenatal period, only 20 (12.9%) were eventually randomised at birth. The main reasons for the high loss were that women either did not have a vaginal delivery (38, 24.5%), or they did not need an episiotomy (72, 46.5%). Rates of obstetric anal sphincter injury and other outcomes were similar between groups.DiscussionAnal sphincter injury during childbirth remains an important problem. Although the use of curved scissors provides a theoretical solution, we found that the high attrition rate made feasibility of conducting a suitably powered, randomised trial using the current design untenable. Alternative strategies have been suggested to make any future study more viable.  相似文献   
146.
The six recommendations made by the Guidelines for Assessment and Instruction in Statistics Education (GAISE) committee were first communicated in 2005 and more formally in 2010. In this article, 25 introductory statistics textbooks are examined to assess how well these textbooks have incorporated the three GAISE recommendations most relevant to implementation in textbooks (statistical literacy and thinking; use of real data; stress concepts over procedures). The implementation of another recommendation (using technology) is described but not assessed. In general, most textbooks appear to be adopting the GAISE recommendations reasonably well in both exposition and exercises. The textbooks are particularly adept at using real data, using real data well, and promoting statistical literacy. Textbooks are less adept—but still rated reasonably well, in general—at explaining concepts over procedures and promoting statistical thinking. In contrast, few textbooks have easy-usable glossaries of statistical terms to assist with understanding of statistical language and literacy development. Supplementary materials for this article are available online.  相似文献   
147.
Head (the intellectual/critical thinking) and Heart (the emotional-interpersonal) are long established twin-pillars of social work. Their importance is not just reflected in literature devoted to each but in the professional proficiencies and capabilities expected for practice. While clearly intertwined—both operate together in practice—and central to practice proficiencies/capabilities, implying implicit measurement of standards, there is a curious lack of research focusing on measurement of the two together. This novel study is the first to carry out a longitudinal comparative study examining the extent to which interpersonal and critical thinking capabilities are developed during the lifetime of qualifying social work training as measured through programme performance and development. It focuses on four cohorts (n = 170) at two Universities (Undergraduate and Masters). While findings show the interpersonal significantly underpinned performance and outcome, critical thinking—though embedded in Masters programme performance—was less significant, particularly in the undergraduate programmes. The study concludes that we cannot assume interpersonal and critical thinking capabilities are always incorporated into the learning process and attention should be paid to the overt measurement of interpersonal and critical thinking capabilities together with the processes and mechanisms by which they are focused on in programmes.  相似文献   
148.
The article presents an approach of Blended Coaching, which was evaluated in an empirical study in the non-profit-sector and emerged as a concept for the profit sector. Blended Business Coaching helps to transfer training contents of advanced vocational trainings into professional daily life. Using special methods, this transfer coaching utilizes the advantages of both face-to-face communication and internet based communication for the continuing education and coaching of the participants. This article shows the results of the empirical study and the approach itself.  相似文献   
149.
In 1935, R.A. Fisher published his well-known “exact” test for 2x2 contingency tables. This test is based on the conditional distribution of a cell entry when the rows and columns marginal totals are held fixed. Tocher (1950) and Lehmann (1959) showed that Fisher s test, when supplemented by randomization, is uniformly most powerful among all the unbiased tests UMPU). However, since all the practical tests for 2x2 tables are nonrandomized - and therefore biased the UMPU test is not necessarily more powerful than other tests of the same or lower size. Inthis work, the two-sided Fisher exact test and the UMPU test are compared with six nonrandomized unconditional exact tests with respect to their power. In both the two-binomial and double dichotomy models, the UMPU test is often less powerful than some of the unconditional tests of the same (or even lower) size. Thus, the assertion that the Tocher-Lehmann modification of Fisher's conditional test is the optimal test for 2x2 tables is unjustified.  相似文献   
150.

In this paper, a simulation experiment has been developed to examine the combined influence of the design, inventory and environmental factors on the cost performance of a rolling horizon master production schedule. Specifically, a 2 5 factorial design was used to examine the effects associated with three rolling schedule design policies, one inventory policy and one environmental condition of forecast error on MPS cost performance. The study was based on actual data from a paint company. Results suggest that the choice of appropriate lot-size and inventory policies have a significant influence on MPS costs and that there are indeed important interactions between these policies and other design factors of a rolling schedule.  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