全文获取类型
收费全文 | 19743篇 |
免费 | 324篇 |
国内免费 | 2篇 |
专业分类
管理学 | 2731篇 |
民族学 | 74篇 |
人才学 | 1篇 |
人口学 | 1710篇 |
丛书文集 | 93篇 |
教育普及 | 2篇 |
理论方法论 | 1798篇 |
综合类 | 419篇 |
社会学 | 9870篇 |
统计学 | 3371篇 |
出版年
2020年 | 271篇 |
2019年 | 329篇 |
2018年 | 374篇 |
2017年 | 527篇 |
2016年 | 422篇 |
2015年 | 327篇 |
2014年 | 402篇 |
2013年 | 3242篇 |
2012年 | 558篇 |
2011年 | 504篇 |
2010年 | 354篇 |
2009年 | 376篇 |
2008年 | 428篇 |
2007年 | 443篇 |
2006年 | 395篇 |
2005年 | 513篇 |
2004年 | 438篇 |
2003年 | 375篇 |
2002年 | 404篇 |
2001年 | 450篇 |
2000年 | 446篇 |
1999年 | 434篇 |
1998年 | 329篇 |
1997年 | 309篇 |
1996年 | 331篇 |
1995年 | 304篇 |
1994年 | 324篇 |
1993年 | 292篇 |
1992年 | 357篇 |
1991年 | 363篇 |
1990年 | 359篇 |
1989年 | 341篇 |
1988年 | 334篇 |
1987年 | 306篇 |
1986年 | 306篇 |
1985年 | 289篇 |
1984年 | 337篇 |
1983年 | 314篇 |
1982年 | 248篇 |
1981年 | 210篇 |
1980年 | 217篇 |
1979年 | 260篇 |
1978年 | 219篇 |
1977年 | 185篇 |
1976年 | 171篇 |
1975年 | 146篇 |
1974年 | 163篇 |
1973年 | 135篇 |
1972年 | 95篇 |
1971年 | 98篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
11.
Fire and restoration of the largest urban forest of the world in Rio de Janeiro City,Brazil 总被引:1,自引:1,他引:0
National Park of Tijuca in Rio de Janeiro (Brazil) is about 3,300 ha and considered the largest urban forest in the world. Its floristic composition is typical of Atlantic Rain Forest. The reserve is being altered because of fire occurrences and urban expansion. This study identified locations and causes of forest fires, and makes management recommendations to restore damaged areas. From 1991 to 2000, forest firefighters recorded an average of 75-fire occurrences/year. Identified causes included hot air balloons (24%), intentional (24%), rubbish burning (21%) and religious practices (17%). Primary fuels included invasive grasses and ferns. Although hot air balloons destroyed larger areas of forest in each occurrence, a greater number of fires started in the invasive vegetation along roads that bisect the forest. In response to recurrent forests, invasive vegetation has spread gradually into the forest increasing forest degradation. To decrease fire damage, sites with high fire frequencies and density of invasive vegetation were planted with less flammable species. Results indicate that fire frequency decreased and density of invasive vegetation declined. This approach appears to prevent fire incidence, reduce the need for fire fighting, and preserve existing biodiversity. 相似文献
12.
Abstract The effect of nonfarm development on dairy farm survival in New York's highly developed lower Hudson Valley is analyzed. The major hypothesis is that significant losses of dairy farms during this period are the result of urban development pressures. Contrary to this hypothesis, however, the bivariate and multivariate analyses of data from a mail survey of all commercial dairy operators in Dutchess County as of 1984 and industry survivors, exiters, and new entrants through 1990 demonstrate that nonfarm development has a negligible effect on dairy farm survival; rather, survival is significantly affected by age of operator and by family disruption. Thus, demographic and family process factors are found to be more powerful determinants of dairy farm survival in this particular metropolitan context. 相似文献
13.
Medical fraud and overservicing are estimated to cost the Australian community between $130 and $200 million per annum, a figure far greater than the national cost of burglary and almost the same as the total property loss from all conventional crime. An examination of the social antecedents of medical fraud and overservicing suggests that the predisposition of some doctors to engage in these practices occurs because of the following: (1) medical training and professional socialization that orientate student doctors away from altruistic health issues towards narrower self-interested professional concerns; (2) career expectations of a high pattern of material consumption that are often frustrated by an increasingly competitive medical market place; and (3) professional medical organizations that lobby for national health policies which reflect the mercenary self-interest of doctors rather than the health interest of the nation. 相似文献
14.
15.
16.
The theory of incapacitation involves reducing an offender's ability or capacity to commit further crimes. Capital punishment accomplishes this goal. An executed murderer never murders again. However, we do not execute all murderers, only capital murderers. This policy produces several research questions. Do capital murderers present a special risk to society? Are capital murderers more likely to murder or commit other violent crimes again than other murderers or the average citizen? To answer these questions, many states require a prediction of future dangerousness of a newly convicted murderer. To what extent has the judgment of future dangerousness matched actuarial data of subsequent murders and serious crimes? Using a secondary analysis, this investigation attempted to assemble available data of postconviction dangerousness of death sentenced capital murderers to create a more comprehensive actuarial account of subsequent dangerousness and to present the data in a common format used by the Federal Bureau of Investigation and the Bureau of Justice Statistics. Across 14 studies identified with relevant data, there were 13 instances of subsequent murder and 462 serious crime or prison rule violations. 相似文献
17.
James R. Vanderwoerd 《Nonprofit management & leadership》2004,14(3):239-262
This article reports selected findings from a qualitative case study of two faith‐based social service organizations to address two questions: (1) How does government funding influence the religious characteristics of faith‐based social service organizations? (2) How do government‐funded, faith‐based social service organizations manage the tensions arising from both secular and religious contexts? The findings suggest that the adaptation of secular institutional practices is not as inevitable as some have feared. Rather, the two organizations studied showed convincingly that their faith traditions and values were alive and widely evident throughout their organizations. Three key strategies emerged as means for maintaining religiousness in the face of secular pressures: (1) Religious identities were perceived as given rather than chosen, and therefore were not negotiable; (2) religious values provided strong justification for seeking relationships with others who do not share their faith; (3) the religious worldview blurred religious and secular distinctions so that secular technologies and practices could comfortably be utilized. 相似文献
18.
19.
Zhu Carolyn W. Moore Michael J. Clipp Elizabeth C. 《Review of Economics of the Household》2003,1(1-2):59-76
Informal caregivers of individuals with Alzheimer's disease spend a considerable amount of time providing care. In this paper, we use Grossman's health production and Becker's time allocation models to develop a model of informal care provision to elderly dementia patients. In our model, time inputs produce caregiving services, which provides utility to the caregiver, but reduces leisure. We assume that time is less productive of services on the margin as the disease progresses. In this framework, an increase in patients' disease severity does not necessarily increase informal caregiver time input. The cost of formal care establishes a reservation price for informal caregiving. When the costs of informal caregiving rise above this reservation level, the patient is institutionalized. We test empirically the effect of deterioration in the patients' condition, proxied by both disease severity and dementia problem behavior, on informal caregiving time. We find that dementia-related problem behaviors and functional limitations significantly increase inputs of informal caregiving time. Patients' problem behavior exerts a modifying effect on functional limitations, and patients' comorbidities have no effect on informal caregiving time. 相似文献
20.
Diagnostics for dependence within time series extremes 总被引:1,自引:0,他引:1
Anthony W. Ledford Jonathan A. Tawn 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2003,65(2):521-543
Summary. The analysis of extreme values within a stationary time series entails various assumptions concerning its long- and short-range dependence. We present a range of new diagnostic tools for assessing whether these assumptions are appropriate and for identifying structure within extreme events. These tools are based on tail characteristics of joint survivor functions but can be implemented by using existing estimation methods for extremes of univariate independent and identically distributed variables. Our diagnostic aids are illustrated through theoretical examples, simulation studies and by application to rainfall and exchange rate data. On the basis of these diagnostics we can explain characteristics that are found in the observed extreme events of these series and also gain insight into the properties of events that are more extreme than those observed. 相似文献